Photocatalyst-carrying structure and photocatalyst coating material

ABSTRACT

The present invention provides a photocatalyst-carrying structure which has a structure, wherein an adhesive layer is provided in between a photocatalyst layer and a substrate, the adhesive layer is composed of silicon-modified resin, polysiloxane-containing resin or colloidal silica-containing resin, and for forming the photocatalyst layer a composition comprising a metal oxide gel or a metal hydroxide gel and a photocatalyst is used. Further, the present invention also provides a photocatalyst coating agent for producing a photocatalyst-carrying structure which contains silicon compound, at least one metal oxide sol or metal hydroxide sol, and at least one photocatalyst powder or sol.

FIELD OF THE INVENTION

The present invention is related to a structure carrying a photocatalystwhich is useful for antifouling, cleaning water, deodorization,pasteurization, a treatment of waste water, decomposition of water, acontrol of algae growth and various chemical reactions.

BACKGROUND ART

Titanium dioxide, which is n-type semiconductor, has been known as aphotocatalyst that activates various chemical reactions with ultravioletradiation energy, such as chemical reactions resulted in during aprocess of decomposition of water, deodorization, pateurization,cleaning of water, a treatment of waste water or the like. It is saidthat the catalytic activity of a photocatalyst can be generally highwhen it is used either in powder form or in a form of suspension in asolvent, however, in many cases, such photocatalyst is practicallyobliged to be used in a form being carried on a certain substrate. Forutilizing ultraviolet radiation energy from light efficiently, it isadvantageous to make a substrate into a shape like a paper or a sheet,which can secure the wider light irradiation area, moreover, it isfurther advantageous to make the surface of the substrate into a porousstructure in order to increase contacting area of the substrate with areactant with which an objective chemical reaction is desired to beproceeded in the presence of a photocatalyst.

Various substrates which comprise a photocatalyst have been proposed inthe past. For example, (A) a light transmissible material, such ascellulose nitrate, glass, poly(vinyl chloride), plastics, nylon,methacrylic resin and polypropylene, is disclosed in Japanese PatentLaid-opened No. Sho 62-66861, (B) polypropylene fibers and ceramics aredisclosed in Japanese Patent Laid-opened No. Hei 2-68190, and (C) glass,ceramics, nylon, acryl and polyester resins are disclosed in JapanesePatent Laid-opened No. Hei 5-309267.

However, among the materials as disclosed above, it is reported that theone comprising an organic material as its main component has thedisadvantage that the organic material can be decomposed anddeteriorated due to catalytic reaction caused by a photocatalystcontained in the said material, and the durability thereof has thereforebeen problematic (see Pumiaki OotaniO Kobunsi Kako No.42, vol.5, page 18(1993); “Titanium dioxide”, by Manabu Kiyono, published by Gihodo, page165).

Further, even though the substrate is composed of an inorganic material,such as glass and ceramics, there must be some problems in thedurability property of the substrate, such that, if an organic polymerresin is used as an adhesive for carrying a photocatalyst on thesubstrate, the photocatalytic activity may be lowered due to coverage ofthe surface of photocatalyst particles with such resin, and that thephotocatalyst may be exfoliated from the substrate due to the cause ofdecomposition and deterioration of said organic polymer resin by virtueof its photocatalytic activity.

In order to avoid having such problems as described above, a methodcalled spattering method whereby any organic materials do not remain(Japanese Patent Laid-opened No. Sho 60-044053), a method to coat andbake an organic titanate (Japanese Patent Laid-opened No. Sho60-118236), a method to spray and bake titania sol (Japanese PatentLaid-opened No. Hei 5-253544), and the others have been employed, incase that the substrate used is an inorganic heat-resistant material.

However, these methods have a problem that they require a process ofbaking the substrate at a high temperature in order to obtain productionand crystalization of photocatalyst particles over the substrate andadhesive property with the substrate, and therefore, it is difficult tocarry photocatalyst over a wide area and the production according tothese methods requires very high cost.

Whereas, for carrying a photocatalyst onto a glass fiber paper, a methodto use a metal oxide sol as an adhesive has been proposed (see JapanesePatent Laid-opened No. Hei 5-309267).

However, the adhesive property of a metal oxide sol, such as silica sol,is very weak because it is derived from van der Waars force (see FineCeramics, vol.1, page 216-223, 1980) so that the binding strength anddurability of the adhesive were insufficient. Further, the methodadditionally requires a process of baking at a high temperature, andtherefore, it was not applicable for all types of substrates includingcommonly used types of resins which are easily decomposed by heating.

In an example wherein a metal oxide, such as silica gel and claymineral, in a sol state carrying photocatalyst powder thereon, there isa report that the photocatalytic decomposition reaction of propionealdehyde gas is accelerated by virtue of the effect of a substrate as anadsorbent (see Symposium, “Recent development in PhotocatalyticReaction”, previous manuscripts, by Society for the Study ofPhotofunctional Materials, No.2-11, page 39, 1994).

However, no report has been made up till now describing that a substratehaving excellent adhesive property and durability while keeping the highphotocatalytic activity of a photocatalyst which is uniformlydistributed in a metal oxide sol as described above is obtained.

Whereas, a method to fix a photocatalyst by using a fluororesin has beenalso proposed (see Japanese Patent Laid-opened No. Hei 6-315614).However, the price of fluororesin is high, and it is required to coverthe most of the surface of photocatalyst particles with fluororesin inorder to stick photocatalyst particles strongly. Accordingly, thecatalytic activity of a photocatalyst becomes lower than the activitygiven by the same photocatalyst in powder form. Although an example thatintends to carry a photocatalyst onto a substrate by means of mixing thephotocatalyst with a binder resistant to decomposition, such asfluororesins and poly(organosiloxane), has been known (see EP-0633064),it is not sufficient to solve practically such problems as to adhesiveproperty and durability.

As described above, the following three points can be given as problemsto be solved when carrying a photocatalyst onto a substrate, which are(1) an adhesive property between a photocatalyst and a substrate shouldbe good, (2) the photocatalytic activity of a photocatalyst does notdegrade when it is carried onto a substrate, and (3) both of a substrateand an adhesive should not be deteriorated due to presence of aphotocatalyst carried thereon and the substrate can keep its bindingstrength, durability and catalytic activity. Furthermore, when using aphotocatalyst-carrying structure under a condition of a high temperatureand high humidity, a property to maintain excellent adhesive propertyafter dipping it into boiling water is required for the structure, forexample.

Whereas, it is required for a photocatalyst coating material used forcarrying a photocatalyst onto a substrate a property that thephotocatalyst coating material causes neither its viscosity increase norits particle sedimentation even after the preservation for at least onemonth and preferably more than three months. Also, a property thatenables to carry a photocatalyst onto a substrate without deterioratingits photocatalytic activity when coating the photocatalyst onto aproduct for practical use, is required as well.

The inventors of the present invention have found a method to stronglyglue a photocatalyst onto a substrate by providing a specific adhesivelayer in between a photocatalyst layer and a substrate to therebyprotect the substrate provided under the adhesive layer from itsdeterioration due to photocatalytic action derived from thephotocatalyst and strongly glue the photocatalyst layer to the substrateand by making the adhesive layer resistant to deterioration due tophotocatalytic action, providing a solution for the problems asdescribed above.

DISCLOSURE OF INVENTION

The inventors of the present invention found that silicon-modifiedresin, such as acryl-silicon resin or epoxy-silicon resin, containing2-60% by weight of silicon, a resin containing 5-40% by weight ofcolloidal silica, and a resin containing 3-60% by weight ofpolysiloxane, which is a polycondensation reaction product of a compoundrepresented by a general formula (1);

SiCln₁(OH)n₂R¹n₃(OR²)n₄  (1)

wherein R¹ is an alkyl having 1-8 carbon atoms which is unsubstituted orsubstituted with any of amino, carboxyl or chlorine atom, R² is an alkylhaving 1-8 carbon atoms or an alkoxy-substituted alkyl having 1-8 carbonatoms, n¹ is 0, 1 or 2, n² and n³ are each independently 0 or any ofintegers of from 1 to 3, n⁴ is any of integers of from 2 to 4, providedthe sum of n¹, n², n³ and n⁴ is 4, can strongly glue a photocatalyst andprotect the substrate from photocatalytic action derived from aphotocatalyst.

Moreover, for solving the problem on the photocatalyst coating material,the inventors of the present invention have found out that aphotocatalyst coating material comprising 0.001-5% by weight of one ormore of alkoxysilanes represented by a general formula (2);

SiR³n₅(OR⁴)₄—n₅  (2)

wherein R³ is an alkyl having 1-8 carbon atoms which is unsubstituted orsubstituted with any of amino, chlorine atom or carboxyl, R⁴ is an alkylhaving 1-8 carbon atoms or an alkoxy-substituted alkyl having 1-8 carbonatoms, n₅ is 0, 1 or 2, or the hydrolysis products thereof, 1-30% byweight of a metal oxide sol and/or a metal hydroxide sol on the solidcomponent basis, and 0.1-30% by weight of a photocatalyst in powderand/or sol, can be stable for a long time and does not result viscosityincrease and particle sedimentaion, and they have accordinglyaccomplished the present invention.

Furthermore, the inventors of the present invention have also found outthat the photocatalyst-carrying structure and the photocatalyst coatingmaterial described above can be carried onto various substrates, such asglass, plastics, metals, cloth and woody materials, and can be coatedonto lens, adhesive films, window shades, nonwoven fabrics, woodendoors, etc. by using the photocatalyst coating material according to thepresent invention.

The present invention is further described in detail in the following.

In the present invention, a resin to be used for forming the adhesivelayer in the photocatalyst-carrying structure is selected from a groupconsisting of silicon-modified resin, such as acryl-silicon resin orepoxy-silicon resin, comprising 2-60% by weight of silicon, a resincomprising 5-40% by weight of colloidal silica and a resin comprising3-60% by weight of polysiloxane.

When any of silicon-modified resin containing silicon at content of lessthan 2% by weight, such as acryl-silicon resin, a resin containingpolysiloxane at a content of less than 3% by weight and a resincontaining colloidal silica at content of less than 5% by weight isused, the binding force between the adhesive layer and the photocatalystlayer degrades, and the adhesive layer is deteriorated due to the actionof a photocatalyst, thereby the photocatalyst layer tends to beexfoliated easily. Whereas, when silicon-modified resin, such asacryl-silicon resin containing silicon at a content more than 60% byweight is used, the binding between the adhesive layer and the substrategets worth and the abrasion-resistant property of the structure degradesbecause of the lowering of the hardness of the adhesive layer.

Whereas, when a resin containing polysiloxane more than 60% by weight ora resin containing colloidal silica more than 40% by weight is used, theadhesive layer becomes porous, the substrate provided under the adhesivelayer deteriorates due to the effect of a photocatalyst, and bindingcondition between the substrate and the adhesive layer degrades, and thephotocatalyst layer thereby tends to be easily exfoliated from thesubstrate.

When using silicon-modified resin, such as acryl-silicon resin andepoxy-silicon resin, as an adhesive layer material, any silicon-modifiedresin prepared according to any method for introducing silicon intoresin, such as an ester exchange method, graft reaction method usingsilicon macromers and reactive silicon monomers, hydrosilylationreaction method and block copolymerization method, can be used in thepresent invention.

As a resin whereto silicon is introduced, acryl resin and epoxy resinare the most suitable in terms of film-forming property, toughness andadhesion property to the substrate, howeverr, other resins, such asalkyd resin, urethane resin and polyester resin, can be used as well. Inaddition, these resins can be used in the either type of solution oremulsion. Also, it is not problematic even though such resin contains anadditive, such as a cross-linking agent.

A photocatalyst-carrying structure with improved adhesive property anddurability can be obtained if a resin used for forming an adhesive layeris polysiloxane, and the polysiloxane is a hydrolysis product of asilicon alkoxide having 1-5 carbon atoms or a product derived from sucha hydrolysis product. If alkoxy group of the silicon alkoxide contains 6or more carbon atoms, such resin becomes costly, and the adhesiveproperty and durability of the resin deteriorate because it is difficultto harden the alkoxide in the resin due to its slow hydrolysis rate.

It is also possible to use polysiloxane which is obtained by subjectingsilicon alkoxide partially containing chlorine to hydrolysis, however, asubstrate may result corrosion due to the presence of chlorine ions asan impurity when using polysiloxane containing a high degree of chlorineatoms, which also degrades the adhesive property of the adhesive layer.

As a method to introduce polysiloxane into a resin, a method to mix itin a form of a silicon alkoxide monomer with a resin solution andsubsequently allowing it to hydrolysis with moisture in the air at thetime of forming an adhesive layer, a method to mix a product obtained bypartially allowing silicon alkoxide to hydrolysis with a resin andsubsequently allowing the mixture to hydrolysis with moisture in the airat the time of forming a protective film, etc. are known, any methodwhich allows an uniform mixing with a resin can be employed. A smallamount of an acid or base catalyst may be added to change the speed ofhydrolysis of silicon alkoxide.

As examples for a resin suitable to be introduced with polysiloxane,acryl resin, acryl-silicon resin, epoxy-silicon resin, silicon-modifiedresin, urethane resin, epoxy resin, polyester resin, alkyd resin, etc.can be given, however, silicon-modified resin including acryl-siliconresin and epoxy-silicon resin are the most preferable one in view oftheir durability property.

If the adhesive layer is composed of a resin that contains colloidalsilica, it is preferable if the diameter of colloidal silica particlesis 10 nm or less. When the diameter exceeds 10 nm, the resin in theadhesive layer further deteriorates due to the influence of aphotocatalyst, and binding condition between the photocatalyst layer andthe adhesive layer become worse as well. As a method to introduce suchcolloidal silica into the resin, it is known that a method to mix aresin solution with a colloidal silica solution, then apply it andsubsequently dry it to form an adhesive layer is the easiest, however, amethod to form an adhesive layer by allowing a resin to polymerizationwhile dispersing colloidal silica in the resin and then to apply thesynthesized resin and dry it, is also acceptable. It is also possible touse colloidal silica after treating it with a silane coupler forimproving adhesive property and dispersibity of colloidal silica and aresin.

As examples for a resin whereto colloidal silica is introduced, acrylresin, acryl-silicon resin, epoxy-silicon resin, silicon-modified resin,urethane resin, epoxy resin, polyester resin, alkyd resin, etc. aregiven, however, silicon-modified resins including acryl-silicon resinand epoxy-silicon resin, are the most suitable one in term ofdurability.

As the colloidal silica, any silica sol, which is produced either bysubjecting sodium silicate solution to cation exchange or by subjectingsilicon alkoxide to hydrolysis, can be used.

Whereas, for a purpose to prevent deterioration of a resin used for anadhesive layer by influence of a photocatalyst and to improve itsdurability, a mixing of the resin with a photostabilizing agent and/oran ultraviolet absorbent or the like may provide a good effect. Asusable photostabilizing agents, it is preferable to use hindered aminecompounds, however, any other compounds can be used as well. Whereas,triazole compounds can be used as an ultraviolet absorbent. The amountof the ultraviolet absorbent to be added to the resin is in a range offrom 0.005% by weight to 10% by weight based on the weight of the resin,and more preferably from 0.01% by weight to 5% by weight. By treatingthe surface of the adhesive layer with a silane-containing ortitan-containing coupler, the binding condition between the adhesivelayer and the photocatalyst layer may be improved.

As a method to carry an adhesive layer on a substrate, a method to coatthe substrate with a resin solution according to any of printing method,sheet molding method, spray blowing method, dipping and coating method,spin coating method, etc. and then to dry the coated-substrate gcan beemployed. The temperature for drying the coated-substrate is preferablyat 150° C. or less, though it differs depending on type of solvents andresins. When a thickness of an adhesive layer is 0.1 μm or more, it ispossible to prepare a photocatalyst-carrying structure which canstrongly bind a photocatalyst layer and a substrate and has highdurability. Whereas, in case of a coating method, such as gravuremethod, which requires a process for drying and curing the adhesivelayer in a short time, it is also allowable to add a curing agent, suchas silicon compounds or the like, into the adhesive layer material from0.1 to 10% by weight based on the weight of the solid component of theadhesive layer material, depending upon hardening speed required.

A metal oxide gel or a metal hydroxide gel presenting in a photocatalystlayer provides an effect to fix photocatalyst powder and to stronglyadhere it to an adhesive layer, and therefore, a photocatalyst-carryingstructure comprising such metal oxide gel and/or metal hydroxide gelshow excellent adhesibity, durability and weather resistance as shown inthe examples of the embodiment for the present invention. In addition,such metal oxide gel and metal hydroxide gel have porous structure andare adsorbate, and they have further an effect to enhance photocatalyticactivity. A preferable range for the content of such metal oxide gel ormetal hydroxide gel in the photocatalyst layer is from 25 to 95% byweight. When this content is less than 25% by weight, the binding withan adhesive layer may be insufficient, whereas photocatalytic activitymay be insufficient when that content exceeds 95% by weight.

Furthermore, the binding described above and the photocatalytic activitycan be improved, when the specific surface area of the metal oxide gelor the metal hydroxide gel after drying at 150° C. is 50 m²/g or more,and more preferably 100 m²/g or more.

As examples for a metal in the metal oxide gel and the metal hydroxidegel as described above, silicon, aluminium, titanium, zirconium,magnesium, niobium, tantalum, tungsten, tin, etc. are given.

The sticking property of a photocatalyst layer after dipping it intoboiling water can be improved by using a metal oxide gel or a metalhydroxide gel comprising 2 or more metals selected from a groupconsisting of silicon, aluminium, titanium, zirconium and niobium. Asexamples for a combination of metal components showing boling waterresistance, silicon-aluminium, silicon-titanium, silicon-zirconium,silicon-niobium, aluminium-titanium, aluminium-zirconium,aluminium-niobium, aluminium-tantalum, titanium-zirconium,titanium-niobium, titanium-tantalum, silicon-aluminium-zirconium andsilicon-aluminium-titanium are given as preferable, and metal oxide gelsand metal hydroxide gels comprising metals, such as silicon-aluminium,silicon-titanium, silicon-zirconium, silicon-titanium-aluminium andsilicon-aluminium-zirconium are given as more preferable ones.

If the specific surface area of these metal oxide gels or metalhydroxide gels is 50 m²/g or more, they provide high sticking propertyand improved photocatalytic activity to a photocatalyst layer, therebyallowing the photocatalyst-carrying structure to retain excellentbinding property even after dipping it into boiling water. In practicaluses, both gels prepared by mixing a sol for forming a gel and complexoxide gels prepared by coprecipitation method or the like may be used.For mixing with a photocatalyst, it is desirable either to uniformly mixa metal oxide or hydroxide in a state of sol before forming gel or tomix in a stage of a raw material before preparing a sol.

As a method to prepare gels, a method to hydrolyze a metal salt, amethod to decompose a metal salt by neutralization, a method to exchangeions, a method to hydrolyze a metal alkoxide, and the like can be given,however, any methods by which the gel is obtained in a state thatphotocatalyst be uniformly dispersed in the gel, are allowable to use.Provided, as the sticking property and the photocatalytic activity of aphotocatalyst may be affected if plenty of impurities are contained inthe gel, it is preferable to use a gel containing less impurities.

Further, by adding either of silicon-modified resin or a silane couplerinto a photocatalyst layer from 10 to 50% by weight, it is possible toobtain a photocatalyst layer which retains high photocatalytic activityand has an excellent binding property evaluated as more than 6 pointsaccording to the adhesive property test, cross-cut Scotch tape testprovided in JIS-K5400 even after dipping it into boiling water for 15minutes.

The silicon-modified resin or a silane coupler to be added into aphotocatalyst layer has an effect to improve the adhesive property ofthe photocatalyst layer to a substrate in boiling water. As thesilicon-modified resin, commonly available resins, such as silicon-acrylresin and silicon-epoxy resin, either in a state of solution in asolvent or suspension in water are usable. Whereas, as the silanecoupler, a compound represented by general formulas, RSi(Y)₃ and (R)₂Si(Y)₂, wherein R is an organic functional group and Y is chlorine atomor alkoxy, and the like are usable. In the general formulas describedabove, methyl, ethyl, vinyl, γ-glycidoxypropyl, γ-methacryloxypropyl,γ-(2-aminoethyl)aminopropyl, γ-chloropropyl, γ-mercaptopropyl,γ-aminopropyl, and γ-acryloxypropyl, etc. are given as the examples fora substituent represented by R, and in addition to chlorine atom, any ofC₁-C₅ alkoxy, such as methoxy, ethoxy, β-methoxyethoxy andβ-ethoxyethoxy, are also usable as a substituent represented by Y.

The amount of silicon-modified resin and a silane coupler to be added toa photocatalyst layer is preferably from 10 to 50% by weight on thesolid component basis. If the such amount is less than 10% by weight,binding property after allowing the layer to boiling water test will bereduced, whereas the added-amount exceeds 50% by weight, remarkabledecrease in photocatalytic activity may be caused. As the method to addeither the silicon-modified resin or the silane coupler into aphotocatalyst layer, a method to add such resin into a photocatalyst ina state of either powder or sol and a method to add them into either ametal oxide sol or a metal hydroxide sol which are used for forming ametal oxide gel and added with a photocatalyst. The addition ofsilicon-modified resin in emulsion to the sol described above isparticularly preferable, since it can improve binding property of aphotocatalyst layer in boiling water with nearly no deacrease ofphotocatalytic activity.

Also, an additive, such as a cross-linking agent, can be combined intothe silicon-modified resin or the silane coupler.

As the photocatalyst of the present invention, any type thereof, such asin powder form, sol and solution, can be usable if it can bind with anadhesive layer and show the photocatalytic activity, when it has beendried at a drying temperature for the photocatalyst layer. When aphotocatalyst in a sol state is used, it is preferable to use the one ofwhich particle diameter is 20 nm or less, and more preferably 10 nm orless, because the transparency of a photocatalytic layer may be improvedand linear permeability thereof increases, and therefore, it isespecially preferable to use such photocatalyst for coating of glasssubstrates and plastic moldings, which are required to be transparent.Furthermore, if color and/or patterns are applied on an underlyingsubstrate, a transparent photocatalyst layer coated with suchphotocatalyst is advantageous because it does not give adverse influenceto colors and/or patterns on the underlying substrates.

As the photocatalyst to be used for the photocatalyst layer according tothe present invention, TiO₂, ZnO, SrTiO₃, CdS, GaP, InP, GaAs, BaTiO₃,KNbO₃, Fe₂O₃, Ta₂O₅, WO₃, SnO₂, Bi₂O₃, NiO, Cu₂O, SiC, SiO₂, MoS₂, InPb,RuO₂, CeO₂ and the like, and mixtures of these photocatalysts with ametal or a metal oxide, such as Pt, Rh, RuO₂, Nb, Cu, Sn, Ni and Fe, canbe used. In addition thereto, all mixtures prepared by adding a metal,such as Pt, Rh, RuO₂, Nb, Cu, Sn, Ni and Fe, into the photocatalyst byusing photocatalyst reduction reaction, are also applicable in thepresent invention. The photocatalytic activity increases along with theincrease of content of a photocatalyst in the photocatalyst layer,howeveer, it is preferable to maintain the content to 75% by weight orless in view of maintaining sufficient binding property.

The photocatalyst coating material according to the present invention ischaracterized in that the solution comprises silicon compound 0.001-5%by weight, a metal oxide sol and/or a metal hydroxide sol 0.1-30% byweight on the solid component basis and a photocatalyst powder and/orsol 0.1-30% by weight on the solid component basis.

As the examples for the silicon compounds added to the photocatalystcoating material of the present invention, alkoxy silane represented bya general formula (2),

SiR³n₅(OR⁴)₄—n₅  (2)

wherein R³ is unsubstituted or substituted alkyl having 1-8 carbon atomswith amino, chlorine atom or caboxyl, R⁴ is an alkyl having 1-8 carbonatoms substituted with alkyl having 1-8 carbon atoms or alkoxy, and n₅is any of 0, 1, 2 and 3, and the mixtures with one or more of thosehydrolyzed products can be used. In the general formula (2), methyl,ethyl, vinyl, γ-glycidoxypropyl, γ-methacryloxypropyl,γ-(2-aminoethyl)aminopropyl, γ-chloropropyl, γ-mercaptopropyl,γ-aminopropyl, γ-acryloxypropyl and the like are given as the examplefor the substituent represented by R³, and C₁-C₈ alkoxy, such asmethoxy, ethoxy, n-propoxy, i-propoxy, n-butoxy, β-ethoxyethoxy and2-ethylhexyloxy, are preferable as examples for the substituentrepresented by —OR⁴. As the example for the silicon compoundsrepresented by the general formula (2), tetramethoxy silane, tetraethoxysilane, methyltrimethoxy silane, methyltriethoxy silane, and mixturesconsisting of one or more hydrolysis products of those compoundsmentioned hereinabove can be preferably given.

By adding a small amount of the silicon compound described above into acoating soluiton for forming a photocatalyst layer, stable coatingmaterial for forming a photocatalyst layer which results in a lessincrease of viscosity and particles sedimentation even preserving it fora long time can be obtained. As to the amount of the silicon compound tobe added to the coating material for forming a photocatalyst layer, itis preferable to add it from 0.001 to 5% by weight on the solidcomponent basis. When the such amount is less than 0.001% by weight, thestability of the coating material for forming a photocatalyst layerbecomes lowered when it is preserved for a long time, whereas aprominent decrease in photocatalytic acitivity will be caused when suchamount to add is more than 5% by weight. As a method to add a siliconcompound into a coating material for forming a photocatalyst layer, amethod to add it into a solution of a photocatalyst in the either formof powder or sol, a method to add it into sol of either a metal oxide ora metal hydroxide, which are added together with a photocatalyst, andthe like can be employed. Alternatively, partly-hydrolyzed siliconcompounds may be added into the coating material. As the siliconcompound to be added into the coating material for forming aphotocatalyst layer has an effect to increase the binding property of aphotocatalyst in boiling water, it is possible to reduce an amount ofthe silicon compound to add when the silane coupler as described aboveor the like has been added into the coating material.

It is preferable to add a metal oxide sol and/or a metal hydroxide sol0.1-30% by weight and photocatalyst powder and/or sol 0.1-30% by weighton the solid component basis relative to the weight of the coatingmaterial for forming a photocatalyst layer, respectively, into the saidcoating soltion.

If a ratio of amount of the metal oxide sol and/or the metal hydroxidesol to add is less than 0.1% by weight, property to bind a photocatalystto a substrate will be insufficient, whereas if the such rate is morethan 30% by weight, the amount of photocatalyst powder and/or sol addedconcurrently is obliged to be reduced, thereby photocatalytic activitywill be lowered. Whereas, photocatalytic activity will be too low if aratio of amount of the photocatalyst powder and/or sol to add is lessthan 0.1% by weight, and a photocatalyst layer will be easily exfoliatedsince the amount of a metal oxide sol and/or a metal hydroxide sol forbinding the layer to a substrate is obliged to be reduced if a ratio ofamount of the photocatalyst powder and/or sol to add is 30% by weight ormore.

The coating material for forming a photocatalyst layer according to thepresent invention is concurrently used with a coating material forforming an adhesive layer, with which an adhesive layer can be formed inbetween a photocatalyst layer and a substrate. As the coating materialfor forming an adhesive layer, a composition which contains from 1 to50% by weight on the solid components basis a silicon-modified resincontaining 2-60% by weight of silicon, a resin containing 3-60% byweight of polysiloxane and a resin containing 5-40% by weight ofcolloidal silica can be used.

As a resin suitable to be used for a coating composition for forming anadhesive layer, it is preferable to use the resins usable for anadhesive layer as described above, by alone or in a mixture with anyother one of such resins. Such a coating composition is then preferableto be prepared either in solution of an organic solvent or in aqueousemulsion and the content of the resin as a solid element is preferablyselected from 1 to 50% by weight. When a coating composition wherein theconcentration of solid content of such resin is 1% or less, the adhesivelayer is formed too thin and the binding of the photocatalyst layer willbe difficult to make. Whereas, when a coating composition wherein theconcentration of the solid content of such resin is 50% or more, theadhesive layer will be formed too thick and it will be difficult toproperly make a coating film and handle such a coating compositionbecause it will get too much viscous.

When forming a photocatalyst layer on an adhesive layer, a suspensionwherein a photocatalyst is dispersed in a sol of either a metal oxide ora metal hydroxide can be applied by coating according to a method whichis the same as the one for forming an adhesive layer. Alternatively, aphotocatalyst can be dispersed in a solution of a precurser of either ametal oxide sol or a metal hydroxide sol and is then prepared to a formof either sol or gel through a process of hydrolysis or neutralizingdecomposition at the coating process. When the sol prepared as describedabove is used, a deflocculant, such as an acid and an alkali, may beadded for improving stability of the sol. Also, it is possible tofurther improve the adhesive property and easiness in handling by addinga surfactant, silane coupler or the like into the sol 5% by weight orless based on the weight of a photocatalyst. Drying temperature at thetime that a photocatalyst layer is formed is preferably from 50 to 200°C., though it differs depending upon the difference in substrates andresin materials used for the adhesive layer.

Though a thicker photocatalyst layer provides higher photocatalyticactivity, there is no big difference in the activity if the thicknessexceeds 5 μm. The photocatalyst layer of which thickness is 5 μm or lessis preferable because it provides high photocatalytic activity and lighttransmitting property that makes the adhesive layer less conspicuous.However, though light transmitting property is improved in case that athickness of the photocatalyst layer is less than 0.1 μm, it is notexpectable to obtain high photocatalytic activity since ultraviolet raythat can be utilized by a photocatalyst is also penetrated through thephotocatalyst layer. Whole light transmittance in total of aphotocatalyst layer and an adhesive layer at a wave length of 550 nmwill be 70% or more, if a thickness of the photocatalyst layer is set toa range of from 0.1 μm to 5 μm and a photocatalyst of which particleshaving a diameter of 40 nm or less and either a matal oxide gel or ametal hydroxide gel of which specific surface area is 100 m²/g or moreare used. In case of a photocatalyst-carrying structure of which wholelight transmittance at a wavelength of 550 nm is 70% or more, visiblelight penetrating through the structure can be used for illumination,whereas such structure will be useful from the ornamental view point asit does not spoil a design on a substrate if the substrate of suchstructure is opaque.

The substrate can be formed in any complex shapes, such as film-like,plate-shaped, tubular, fiber-like and reticular, and the adhesive layerand the photocatalyst layer can be provided to any of the such substrateto thereby form a desired photocatalyst-carrying structure. As to thesize of the substrate, it can carry both the adhesive layer and thephotocatalyst layer if it has a size of 10 μm or more. Even an organicpolymer which is not allowable to be heated at the time of coating and ametal which is easily oxidized and corrosive by heating or with waterare used for the materials for the substrate, it is possible to preparea structure whereto an adhesive layer and a photocatalyst layer areprovided, which may show both high photocatalytic activity and highdurability. In order to improve the close adherence between a substrateand an adhesive layer, a substrate of which surface is subjected todischarging process, primer process and the like can be used as well.

As indicated in the examples described below in this specification, thephotocatalyst-carrying structure according to the present invention isuseful for paints for architectural use, wall papers, window glass,blinds, curtains, carpets, illumination appliances, lightings, blacklights, paints for a ship bottom and fishing nets, fillers for watertreatment, vinylchloride films for agricultural use, sheets forpreventing growth of weeds, packaging materials, etc. In addition, thephotocatalyst-carrying structure can be made to a structure which isusable under a high temperature and highly humid condition.

According to the present invention, it is possible to provide astructure carrying an adhesive layer and a photocatalyst layer havinghigh durable property being expressed as an evaluating point of 6 ormore in an adhesive property test according to a method called cross-cutScotch tape test provied in JIS K5400 even after exposing it to blacklight having an ultraviolet radiation intensity of 3 mW/cm² for 500hours at 40° C. and 90% R.H. Additionally, in an accelerated weatheringtest by using Sunshine weather meter, a phtocatalyst-carrying structureable to show such a excellent weathering resistance being expressed asan evaluating point of 6 or more in an adhesive property test for 500hours according to said cross-cut Scotch tape test provided in JIS K5400has been obtained. Furthermore, a structure which shows high resistanceto boiling water such that the adhesive property of the structureevaluated by cross-cut Scotch tape test provided in JIS K5400 afterdipping in boiling water having an electric conductivity of 200 μS/cm at20° C. for 15 min. is expressed as an evaluating point of 6 or more.Since high photocatalytic activity is observed in any samples of thestructures, it is understood that the structure according to the presentinvention has satisfactory properties with regard to various uses asdescribed above.

When a substrate is made of glass, the glass can be formed in anycomplex shapes, such as plate-shaped, tubular, ballshaped andfiber-like, and is provided with said adhesive layer and saidphotocatalyst layer. As to the size, such glass can carry firmly if itis 10 μm or more in size. Moreover, depending upon its usages for, suchas window glass, show cases and glasses, it is also possible to applysuch layers to the processed glass to thereby make aphotocatalyst-carrying glass according to the present invention.

The photocatalyst-carrying glass according to the present invention canbe used for various items which require antimicrobial, deodorant andantisoiling effect, such as cameras and lens for glasses, as well aswindow glass, cover glass for instruments, illumination appliances,lightings, black light blue fluorescent lamps and fillers for watertreatment.

A plastic molding carrying a photocatalyst according to the presentinvention can be used for various uses which require antimicrobial,deodorant and antisoiling effect, such as cameras and lens for glasses,as well as wall papers, board for interior decoration, furnishings,electric appliances, and parts for carriages.

Regarding the shape of the plastic molding described above, any complexshapes, such as film-like, plate-shaped, tubular, ball-shaped andfiber-like, can be used for manufacturing a structure made of plasticmolding provided with said adhesive layer and said photocatalyst layer.As to the size, such plastic moldings can carry such layers firmly ifits size is 10 μm or more. Furthermore, depending upon the usages, suchas for construction materials, electric appliances for home use andglasses, it is also possible to apply such layers to the plastic moldingto thereby manufature a photocatalyst-carrying plastic molding accordingto the present invention, and therefore, it is understood that thestructure of the present invention has substantially a wide applicationrange for use.

Many kinds of cloth can be used for the substrate of the presentinvention; textiles, knit cloth, and nonwoven fabrics comprising singleor mixed fibers consisting of natural fibers, such as wool, silk, cottonand hemp yarn, regenerated fibers, such as rayon and acetate, syntheticfibers, such as nylon, acryl, polyamide, polyester, polyacrylnitrile andpolyvinyl chloride, and heat-resistant fibers, such as aramid fibers,are given as the examples. Also, as the structure of the presentinvention, a cloth applied with a water repelent, such assilicon-containing water repelent, fluorine-containing water repelentincluding perfluoroalkyl acrylate, zirconium salt-containing waterrepelent and ethylene urea-containing water repelent, a cloth treatedwith both water repelent and a cross-linking agent, such as ethyleneimine, epoxy and melamine compounds, for improving durability, ifappropriate, an imitation leather consisting of fibril-formed complexfiber of polyamide and polyester, and a synthetic leather wherein apolyurethane resin layer is formed on a substrate, such as textile,nonwoven fabric and knit cloth, via a binder made of polyurethane. Also,by applying such a water repelent and the like to clothes beingprocessed to umbrellas, tents, bags, etc., the photocatalyst-carryingclothes according to the present invention can be obtained.

The photocatalyst-carrying cloth specified in the present invention isapplicable for various uses which require antimicrobial, deodrant andsoiling resistant effect, for example, interior decoration, such ascurtains and wall papers, tents, umbrellas, daily necessities like tablecloth, food package materials and the like, and agricultural use, suchas sheets for seedling beds.

For the photocatalyst-carrying metal according to the present invention,an alloy, such as stainless steel, brass, aluminium alloy and titanalloy, can be used as a substrate as well as single-element metals, suchas aluminium, iron and copper. Additionally, in case that it isallowable from the configuration and quality point of view of a metal touse, it is also possible to carry both an adhesive layer and aphotocatalyst layer according to the present invention onto thesubstrate, such as a metal sheet and plate painted with normalcolorings, and a colored steel plate or aluminium plate. In this case,it is further preferable that, if the light transmittance of bothadhesive layer and photocatalyst layer is sufficiently high andtransparent, such layers do not give bad influence to the color on theunderlying substrate.

As to the configuration of the metal, there is no difficulty to make theconfiguration of the metal into any complex shape, such as plate-shaped,tubular, ball-shaped, fiber-like and sheet-shaped, to carry suchadhesive layer and photocatalyst layer thereon. And, the metal can carrysuch layers firmly if the size thereof is 10 μm or larger. Furthermore,depending upon the usages, for example, for window flames, show casesand flames for glasses, all of which have been processed, thephotocatalyst-carrying metal according to the present invention can bemanufactured by applying such layers to the metals having beenprocessed.

The photocatalyst-carrying metal according to the present invention canbe used for various uses which require antimicrobial, deodrant andsoiling resistant effect, for example, strainers, filters and the likeas well as window flames, furnishings, accessories and decoration,panels for interior and exterior decoration, fillers for watertreatment, etc.

As to the configuration of timbers and woody materials whereto theadhesive layer and the photocatalyst layer according to the presentinvention are provided, any complex configuration, such as plate-like,tubular, ball-shaped and sheet-like, can be employed. Such timbers orwoody materials can sufficiently carry such layers thereon if their sizeare 10 μm or larger, and it is allowable to manufacture aphotocatalyst-carrying timber or woody material according to the presentinvention by applying such layers onto the such timber and woodymaterial, such as walls, ceiling boards, columns, furnishings andwoodworks, which have been processed beforehand.

The timber and woody material carrying a photocatalyst according to thepresent invention can be applied for various uses which requireantimicrobial, deodrant and soiling resistant effect, for example, forconstruction materials, furnishings, woodworks, and materials forinterior decoration.

By taking advantageous properties, such as soiling resistant,antimicrobial and deodorant function, a plastic film provided with thephotocatalyst-carrying structure according to the present invention canbe made as films of which face, whereto a photocatalyst is not carried,is applied with an adhesive, and such films can be applied to the innerface of window glass of a structure, such as cars and varioustransportation means, buildings, freezing and cooling show cases andgreenhouses, thereby with such glass allowing to providehighly-transmissible glass which expedites decomposition of traceharmful substance existing in the inner space and has soiling resistanteffect on a glass surface and preventive effect to glass spattering atits destruction. When the photocatalyst-carrying structure according tothe present invention is prepared by using a thin plastic film as asubstrate, it can be used as a wrap film for food package use. As aresin applicable for such plastic films, a resin, such aspolyethylene-telephthalate resin, polycarbonate resin, polyacrylateester resin, polymethylmethacrylate resin, polyethylene resin,polypropylene resin, polyamide resin, polyimide resin, polystyreneresin, poly(vinyl chloride) resin, poly(vinylidene fluoride) resin,ethylene fluoride-propylene copolymer resin and ethylenefluoride-ethylene copolymer resin, which can be molded into a highlytransmissive synthetic resin film or sheet of which linear lighttransmittance at a wavelength of 550 nm is 50% or more can be used.Furthermore, since the photocatalyst-carrying structure according to thepresent invention is transparent, it does not give bad influence ondesign and patterns printed on the surface of the underlying wall papersand decoration sheets so that the photocatalyst layer can be appliedadvantageously onto the surface of an opaque material, such as wallpapers and decoration sheets, provided with an adhesive layer and adetachable film layer on its background.

In these synthetic resin films or sheets described above, it is possibleto improve the adhesive property of the adhesive layer in thephotocatalyst-carrying structure by treating the surface of such filmsand the sheets, of which surface whereto an adhesive layer is applied,are physically subjected to trace amount oxidization by corona dischargetreatment and UV-ozone treatment and the ones of which contact with anadhesive layer are improved by slight application of a surface treatingagent, such as silicon-containing compounds, can be used advantageously.

In addition, as shown in the examples for the embodiment of the presentinvention, it is also possible to fix a thin film on the surface or thebackground of such materials for providing reflecting and shadingfunction against thermic rays and ultraviolet ray, thereby thermic raysreflecting films and ultraviolet ray interrupting films concurrentlyhaving soiling resistant, antimicrobial and deodorant function becomeobtainable. It is understood that the photocatalyst-carrying structureaccording to the present invention has both excellently high durabilityand photocatalytic activity, and therefore, it could be exceedinglyuseful and valuable product.

As a method to provide the thermic rays reflecting function describedabove, various methods, such as a method to form a film onto a filmsurface with an electroconductive metal, such as Al, Ag, Cu, Cr, Ni, Ti,stainless and aluminium alloy, or an electroconductive metal oxide, suchas indium oxide, tin oxide and tin oxide-indium oxide compound,according to a physical means, such as sputtering and vacuumevaporation, a method to form a film onto a film surface by means ofapplying and then drying an electroconductive metal oxide soluiton orsol onto the film surface or employing either plating method or CVDmethod and a method to admix a material having thermic rays reflectingproperty and/or thermic rays interrupting property into the substrate,can be employed. Yet, as a method to provide ultraviolet rayinterrupting function, various methods, such as a method to form a filmonto a film surface by applying an ultraviolet ray absorbent, such ashindered amine-containing compounds and titanium oxide, and anultraviolet ray reflecting agent and a method to admix an ultravioletray absorbent into a film substrate beforehand, are allowed to employand is selectable depending upon its use purpose and chemicalstructures. When titanium dioxide is used as ultraviolet ray blocker orultraviolet ray reflecting agent, it is preferable to use the one whichhas lost its photocatalytic activity due to slight coating of thesurface of titatium dioxide with soluble glass or the like, becausesurrounding organic materials are decomposed due to photocatalyticaction if titanium dioxide is existing alone, as explained in detail inthe present invention.

Materials having thermic rays reflecting function and ultraviolet rayblocking function can be incorporated into a sticker layer which isformed on the background of a film to provide such functions. Forexample, a material like ultraviolet blocking clear coating agentdescribed in “Convertec”, March 1996, page 95, is solvent-dispersibletype and is applicable for the above purpose. Stickers, such asacryl-type and silicon-containing compounds are normally used, however,it is also feasible to add various types of ultraviolet ray blockingagents and thermic rays blocking agents. Considering spoil caused withthe remainning sticker at the time of renewal the photocatalyst carryingfilm, it is advisable to avoid the use of a sticker having strongbinding property. As a method to provide a sticker and a detachable filmonto a photocatalyst-carrying film, a method to firstly coat a stickerin solution to the reverse side of the film by means of gravure printingand then dry and roll the coated-film together with detachablepolypropylene film while laminating it therewith is simple and may bepreferably employed.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a chart for the cross section of the photocatalyst-carryingstructure according to the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

The present invention is definitely explained with referring theexamples described below, however, the present invention should not belimited to the scope described in such examples.

Evaluation Method

1) Evaluation of Photocatalytic Activity

A sample carrying a photocatalyst with a dimension of 70 mm×70 mm isplaced in a 4-liters Pyrex glass container. A mixed gas consisting ofair and acetaldehyde was introduced in this container and theconcentration of the acetaldehyde was set to 500 ppm. The sample wasexposed to black light (Type: FL 15BL-B; Manufactured by MatsushitaElectric Industry Co., Ltd.) with an ultraviolet ray intensity of 2mW/cm² for 2 hours. Then, a concentration of acetaldehyde gas in thecontainer was determined by using gas chromatography, and photocatalyticactivity was determined based on the decreased amount of theconcentration. Criterion for the evaluation was provided as follows.

Acetaldehyde Gas Concentration after 2 Hours Evaluated Rank <50 ppm  A 50-200 ppm B 200-300 ppm C 300-450 ppm D 450 ppm< E

2) Evaluation of Adhesive Property

Evaluation of adhesive property was carried out according to cross-cutScotch tape test which is provided in JIS K 5400. A distance betweencross-cut lines set to 2 mm, and the number of squares is fixed to 25.Evaluated point was accorded to a criterion described in JIS K 5400.

3) Dipping Test into Boiling Water

Tap water with an electric conductivity ranging from 170 to 230 μS/cmwas placed into a 1000 ml Pyrex glass beaker together with small amountof zeolite, the sample cut into a size of 70 mm×70 mm was hanged intoboiling water by using a normal clip to let the whole sample sink intowater after heating and boiling water. After 15 min. dipping in boilingwater, the sample was allowed to cooling and drying at a roomtemperature for 4 hours, then the adhesive property test described inthe paragraph 2) was conducted to obtain evaluated-points according tothe criterion described in JIS K 5400.

4) Whole Light Transmittance

Whole ligt transmittance at a wavelength of 550 nm of the samplecarrying an adhesive layer and a photocatalyst layer was measured byusing an automatically-recording spectrophotometer (Type: U-4000,Manufactured by Hitachi Seisakusho) with referring a substrate which hasnot yet carried an adhesive layer and a photocatalyst layer.

5) Evaluation of Durability

The carrying sample was allowed to radiation of black light with anultraviolet ray intensity of 3 mW/cm² for 500 hours in a chambermaintained at 40° C. and 90% R.H., then the adhesive property testdescribed in the paragraph 2) was conducted to obtain evaluated-pointsaccording to the criterion described in JIS K 5400.

6) Accelerated Weathering Test by Using Sunshine Carbon Arc WeatherMeter

Accelerated weathering test by using sunshine carbon arc weather meterprovided in JIS K 5400 was conducted by using the same meter (Type:WEL-SUN-HCH; Manufactured by Suga Shikenki Co., Ltd.) at a condition,namely, test duration of 500 hours, black panel temperature of 63° C.,120 min. cycle and 18 min. rainfall. 3 pieces of the samples wereallowed to the accelerated weathering test, then the samples werevisually evaluated in terms of swelling, cracking, peeling off,whitening and surface change in comparison with the original test pieceswhich are before subjecting it to the accelerated weathering testaccording to the following criterion.

Evaluated-rank Criterion for Evaluation A All of 3 samples showed nochange. B 1 or 2 samples showed slight change. C All of 3 samples showedslight change, or 1 or 2 samples showed apparently great change.

After conducting this test, the adhesive property test as described inthe paragraph 2) was then conducted to obtain evaluated-points accordingto a criterion described in JIS K 5400.

7) Test Method for Antimicrobial Property

The sample cut into a piece with a dimension of 5×5 cm is disinfectedwith 80% ethanol and then dried at 150° C., and 0.2 ml of a bacterialsuspension of colon bacillus, which was cultivated and dilutedbeforehand, to a concentration of 10⁵/ml was fed dropwise to the surfaceof the sample and placed in an incubator. For each radiation condition,4 samples were provided for the test, respectively, namely, 4 samplesfor black light radiation (15 W×2 lamps, distance between a light sourceand the sample is 10 cm), 4 samples for flourescent lamp radiation (15W×2 lamps, distance between a light source and the sample is 10 cm), andanother 4 samples for no light radiation were provided. Afterpredetermined time lapsed (after 1, 2, 3 and 4 hours), the samples weretaken out and the bacterial solution attached to the samples was wipedoff by using disinfected gauze rinsed in sterilized physiological salinesolution. The sterilized gauze used was put into 10 ml sterilizedphysiological saline and throughly stirred. The supernatant of thebacterial solution obtained was inoculated to an agar medium prepared ina petri dish having a diameter of 95 mm which is sterilized by using anautoclave. Then, number of the colonies of colon bacillus cultivated at36° C. for 24 hours was counted. Another sample obtained according tothe same prodedure from dropping of the bacterial solution throughplacing into an incubator was treated according to the same method asdescribed above, and the number of colonies of colon bacillus wascounted. Based on the counted-number, the survival rate of the bacteriaafter each predetermined time was calculated for each group exposed tono light, black light and flourescent lamp, respectively. The evaluationcriterion accorded to the following.

Survival Rate (%) of Clon Bacillus after 4 Hours Evaluated-rank <20% A20-40% B 40-60% C 60-80% D 80%< E

8) Evaluation of Soiling Resistant Property (Decomposition Activity ofFat and Oil)

As an index to evaluate soiling resistant function of the sample, adecomposed amount of common salad oil mainly composed of linoleic acidon a photocatalyst-carrying structure was qualitatively determined inorder to know how fast can fat and oil attached on the surface bedecomposed. To the surface of a photocatalyst-carrying structure cutinto pieces with a dimension of 5×5 cm, salad oil was applied slightlyat a dose of 0.1-0.15 mg/ced by using a paper. The quantity applied wascalculated from the difference of the weight of the structure before andafter an application of oil that were measured by using an acuratebalance. As an index of soiling resistant property, decomposed amountsof salad oil after predetermined time were determined by adjusting thedistance between the sample and black light to take a point where anultraviolet ray intensity on a surface of the sample becomes 3 mW/cm²and calculating the relationship between lapsing time and weightdecrease amount after lighting black light.

Remaining rate (%) of Salad Oil after 24 Hours Light IrradiationEvaluated-rank <10% A 30-10% B 50-30% C 80-50% D 80%< E

EXAMPLES

As a material for a substrate, the following were used.

(TA) Primer-treated polyester film

(TB) Vinyl chloride film

(TC) Soda lime glass plate

(TD) Metal aluminium plate

(TE) High-density polyethylene mesh (Thickness of fiber: 0.2 mm, Meshsize: 0.6 mm)

(TF) Polypropylene tube (Inner diameter: 30 mm, Outer diameter: 36 mm)

As polysiloxane contained in an adhesive layer, the followings wereused.

(PS-1) Silicon tetramethoxide monomer (Manufactured by Shinetsu ChemicalIndustry Co., Ltd.)

(PS-2) Polymethoxy siloxane (Manufactured by Colcoat Co., Ltd., TradeName: Methyl silicate 51)

(PS-3) Polyethoxy siloxane (Manufactured by Colcoat Co., Ltd., TradeName: Ethyl silicate 40)

As colloidal silica contained in an adhesive layer, the followings wereused.

(KS-1) Trade Name: Cataloid SI-350 (Manufactured by Shokubai Kagaku Co.,Ltd., Particle diameter: 7-9 nm)

(KS-2) Trade Name: Snowtex ST-XS (Manufactured by Nissan ChemicalIndustries Co., Ltd., Particle diameter: 4-6 nm)

As a resin solution whereto polysiloxane or colloidal silica isintroduced, the followings were used.

(J-1) 3% by weight of silicon containing acryl-silicon resin solution inxylene

(J-2) 10% by weight of silicon containing acryl-silicon resin solutionin xylene

(J-3) 20% by weight of silicon containing acryl-silicon resin emulsionin water

(J-4) 50% by weight of silicon containing acryl-silicon resin emulsionin water

(J-5) 10% by weight of silicon containing polyester-silicon resinsolution in xylene

(J-6) Acryl resin solution in xylene

(J-7) Polyester resin solution in xylene

(J-8) 3% by weight of silicon containing epoxy-silicon resin solution inmethylethylketone

Either polysiloxane or colloidal silica was mixed with a resin solution,and the mixture obtained was diluted to a certain concentration tothereby prepare a solution to be used for forming an adhesive layer. Theadhesive layer was formed by employing dipping method when a thicknessof the layer is 2 μm or less and the configuration thereof is other thanplate-like, whereas it is formed by using baker applicator when thethickness is 2 μm or more and the configuration thereof is plate-like.In particular, the adhesive layer is formed according to dipping methodwhen the configuration of the substrate is tubular or reticular. Dryingprocess for the adhesive layer was taken place at 80° C. when thematerial of the substrate is (TE) or (TF), and at 60° C. when thematerial is (TB), and at 120° C. in all other cases.

For the photocatalyst, the following materials were used.

(C-1) Fine powder of titanium dioxide (Manufactured by Nihon AerozilCo., Ltd., Trade Name: P-25, diameter of crystallite size: 27 nm)

(C-2) Titanium dioxide sol (sol acidified with nitric acid, diameter ofcrystallite size: 10 nm)

(C-3) Titanium dioxide sol (weak alkaline sol of pH 9.0, diameter ofcrystallite size: 20 nm)

A metal oxide sol or a metal hydroxide sol carried together with aphotocatalyst was obtained by drying any of the following materials insol.

(Z-1) Silica sol: Manufactured by Shokubai Kasei Co., Ltd., Trade Name:Cataloid SI-30, specific surface area after drying at 150° C.: 180 m²/g

(Z-2) Alumina sol: Manufactured by Nissan Chemical Industries Co., Ltd.,Trade Name: Alumina Sol-200, specific surface area after drying at 150°C.: 400 m²/g

(Z-3) Zirconia sol: This is obtainable by allowing zirconiumtetrabutoxide (TBZR; Manufactured by Nippon Soda Co., Ltd.,) tohydrolyzation in ethanol, drying at 150° C., then heating at 300-500°C., and further allowing to deflocculation with a diluted aqueoussolution of nitric acid. Specific surface area of further dried productat 150° C. of the deflocculated-sol is in a range of from 50 to 80m²/g.

(Z-4) Niobium oxide sol: This is obtainable by allowing aqueous solutionof niobium oxalate manufactured by CBMM Co., Ltd. to neutrization with10% aqueous ammonia, drying at 150° C., and then allowing todeflocculation with a diluted aqueous solution of nitric acid. Specificsurface area of further dried product at 150° C. of thedeflocculated-sol is 60 m²/g.

(Z-5) 20% by weight of silicon containing acryl-silicon resin emulsionin water

(Z-6) Silane coupler, tri(β-methoxyethoxy)vinyl silane (Trade Name:A-172), manufactured by Nippon Uniker Co., Ltd.

A solution used for forming a photocatalyst layer was prepared bydispersing titanium dioxide into the solution obtained as describedabove and adding a predetermined amount of a surfactant. Thephotocatalyst layer was formed by dipping method when the thickness ofthe layer is 2 μm or less and/or the configuration of a substrate is theone other than plate-like, whereas the photocatalyst layer was formed byusing bar coater when the substrate is plate and its thickness is 2 μmor more. Drying process for the photocatalyst layer was taken place atthe same temperature as for drying the adhesive layer.

Hereunder, compositions disclosed in the examples for the embodiment ofthe present invention and reference examples, wherein type, quantityand/or thickness of materials, and/or method for forming films aredifferent, and performances of the photocatalyst-carrying structure aredescribed in Tables 1 through 4.

In the examples 1 through 18 and the reference examples 1 through 4,titanium dioxide (P-25) manufactured by Nihon Aerozil Co., Ltd., whichis represented at (C-1), was used as a photocatalyst. The result isshown in Table 1.

TABLE 1 Thick- Adhesive Whole Thick- ness of Property Light AdhesiveLayer Photocatalyst ness of Photoca- Before After Trans- Resin LayerAdhesive talyst Photo- Dura- Dura- mit- Polysiloxane Colloidal SilicaSolu- Metal Oxide Sol Layer Layer catalytic bility bility tance CarrierType Content*1 Type Content*1 tion Type Content*2 (μm) (μm) ActivityTest Test (%) Example-1 TA — — — — J-2 Z-1 50 10 3 B  8  6 82 Example-2TC — — — — J-5 Z-1 75  5 5 B 10  8 75 Example-3 TA PS-1 10 — — J-1 Z-150  5 3 A 10 10 82 Example-4 TA PS-1 20 — — J-2 Z-1 75  5 5 A 10 10 80Example-5 TC PS-2  5 — — J-1 Z-1 50  1 0.5 A 10 10 90 Example-6 TB PS-220 — — J-2 Z-1 30  5 2 A 10  8 85 Example-7 TA PS-2 50 — — J-6 Z-1 70  10.5 B  8  8 90 Example-8 TE PS-2 20 — — J-2 Z-1 50 (*3) (*3) C (*4) (*4)(*5) Example-9 TF PS-2 35 — — J-5 Z-1 60 10 5 A 10 10 (*5) Example-10 TDPS-3 20 — — J-1 Z-1 50 10 7 A 10  8 (*5) Example-11 TD PS-3 20 — — J-2Z-2 80  5 1 B 10  8 (*5) Example-12 TA PS-3 10 — — J-7 Z-1 50 10 5 A  8 8 72 *1: Percent by weight as SiO₂ contained in a dried adhesive layer.*2: Percent by weight of either a metal oxide gel or a metal hydroxidegel contained in a dried adhesive layer. *3: The measurement ofthickness could not be done. *4: No detachment was observed afterultrasonification for 10 min. *5: The determination could not be madebecause of complex configuration and opaque property of the carrier. *6:In example 35, sol wherein silica-alumina component is compounded atthis ratio beforehand is used. Thick- Adhesive Whole Thick- ness ofProperty Light Adhesive Layer Photocatalyst ness of Photoca- BeforeAfter Trans- Resin Layer Adhesive talyst Photo- Dura- Dura- mit-Polysiloxane Colloidal Silica Solu- Metal Oxide Sol Layer Layercatalytic bility bility tance Carrier Type Content*1 Type Content*1 tionType Content*2 (μm) (μm) Activity Test Test (%) Example-13 TA — — KS-120 J-3 Z-1 50 10 3 A 10  8 82 Example-14 Tb — — KS-1 10 J-4 Z-1 40 10 5A  8  6 75 Example-15 TA — — KS-2 20 J-3 Z-1 50  5 3 A 10  8 82Example-16 TD — — KS-2 35 J-4 Z-1 50  2 1 B 10 10 (*5) Example-17 TA — —KS-2 10 J-3 Z-1 50 0.5 0.1 C 10 10 90 Example-18 TC — — KS-2 20 J-7 Z-170  5 2 B  8  6 72 Reference TA — — — — — Z-1 50 — 2 B  0  0 50Example-1 Reference TA PS-2 70 — — J-1 Z-1 50  5 3 E (*6) (*6) (*6)Example-2 Reference TC — — KS-2 50 J-3 Z-1 50  5 2 B  2  0 10 Example-3Reference TC PS-2 20 — — J-2 Z-1 20  5 5 A  2  2 20 Example-4 *1:Percent by weight as SiO₂ contained in a dried adhesive layer. *2:Percent by weight of either a metal oxide gel or a metal hydroxide gelcontained in a dried adhesive layer. *3: The measurement of thicknesscould not be done. *4: No detachment was observed afterultrasonification for 10 min. *5: The determination could not be madebecause of complex configuration and opaque property of the carrier. *6:The determination could not be made because the photocatalyst layer wasexfoliated at the time of formation.

In reference example 1, a structure carrying a photocatalyst layerwithout providing an adhesive layer is given. In this case, thephtocatalyst layer has no sticking property and is easily defoliated.Furthermore, after durability test, the surface of polyester filmdeteriorated due to a photocatalytic effect, and holes and cracks wereobserved on the film.

In examples 1 and 2, a structure wherein either acryl-silicon resin orpolyester-silicon resin is used as an adhesive layer is given. In thiscase, the addhesive property of a photocatalyst layer and durability ofthe structure was found to be excellent.

In examples 3 through 12, a structure wherein a resin containingpolysiloxane is used as the adhesive layer is given. In this case,adhesive property and durability was improved. As well as the resincontaining poysiloxane, acryl-silicon resin (see examples 3, 4 and 5)and polyester-silicon resin (see example 9) had also acquired gooddurability. Further, the resin containing polysiloxane was found to bereplaceable with either acryl resin (see example 7) or polyester resin(example 12), both of which provided excellent property to thestructure.

Contrary, as shown in reference example 2, even though usingacryl-silicon resin containing polysiloxane for the adhesive layer, aphotocatalyst layer lost its adhesive property and was defoliated fromthe adhesive layer when the content of polysiloxane in the adhesivelayer is increased up to 70% by weight.

In examples 13 through 18, a structure wherein a resin containingcolloidal silica was used as the adhesive layer is given. In thesecases, all of photocatalytic activity, adhesive property and durabilitywere found to be excellent. In particular, when acryl-silicon resin andcolloidal silica in fine particle size (KS-2) were used (examples 15 and16), the resulting adhesive layer was found to be very good.

Contrary, when increasing the content of colloidal silica in theadhesive layer up to 50% by weight, both adhesive property anddurability were become worse radically.

In examples 1 through 18, titanium dioxide (P-25) manufactured by NihonAerozil Co., Ltd. represented by (C-1) was used as a photocatalyst, andsilica sol was used in most cases as a metal oxide sol or a metalhydroxide sol to be compounded to the photocatalyst layer, and thestructures in all examples are provided with excellent properties. Inexamples 8 and 9, the structures wherein both layers are carried on asubstrate made of polyethylene mesh or polypropylene tube weredisclosed, and it is demonstrated that these structures show excellentphotocatalytic activity, adhesive property and durability. It is alsofound that such excellent property was still noticeable even decreasingthe content of silica sol in the photocatalyst layer down to 30% byweight (see example 6), however, both adhesive property and durabilityradically deteriorated when reducing the content down to 20% by weight(see example 4).

In example 11, a structure wherein alumina sol was used instead ofsilica sol is given, and this structure is also found as excellent inthe property as well as using silica sol.

In example 17, a structure wherein a thickness of an adhesive layer anda photocatalyst layer was set to 0.5 μm and 0.1 μm, respectively.

In this case, both adhesive property and durability were excellent, andphotocatalytic activity was found to be very high even the thickness ofthe photocatalyst layer was very thin.

Data obtained in examples 19 through 23 are shown in Table 2.

TABLE 2 Thick- Adhesive Whole Thick- ness of Property Light AdhesiveLayer Photocatalyst ness of Photoca- Before After Trans- Resin LayerAdhesive talyst Photo- Dura- Dura- mit- Polysiloxane Solu- Metal OxideSol Layer Layer catalytic bility bility tance Carrier Type Content*1tion Type Content*2 (μm) (μm) Activity Test Test (%) Example-19 TC PS-235 J-1 Z-1 50 5 3 A 10 10 93 Example-20 TC PS-2 35 J-1  Z-3*3 50 5 3 A10 10 82 Example-21 TA PS-2 35 J-5 Z-1 60 3 3 A 10 10 95 Example-22 TCPS-2 35 J-5 Z-1 60 3 2 A 10 10 90 Example-23 TA PS-3 10  J-8*4 Z-1 5010  5 A 10 10 80 *1: Percent by weight as SiO₂ contained in a driedadhesive layer. *2: Percent by weight of either a metal oxide gel or ametal hydroxide gel contained in a dried adhesive layer. *3: An uniformsolution prepared by mixing alumina sol and silica sol at a mixing ratioof 1:1 was used. *4: Mtheyl ethyl ketone solution of epoxy-silicon resincontaining 3% by weight of silicon was used.

Example 19 Use of Titania Sol

A coating material to be used for forming a photocatalyst layer wasprepared by adding and dispersing titania sol containing 12% by weightof titanium dioxide and acidified with nitric acid, which is asubstitute of fine granule titanium dioxide (P-25) manufactred by NihonAerozil Co., Ltd., into silica gel (Trade name: Cataloid SI-30,Manufactured by Shokubai Kasei Co., Ltd.) being adjusted to pH 1.5 andthen further adding a surfactant. Whereas, a solution to be used for anadhesive layer was prepared by adding polymethoxy siloxane (PS-2) into aresin solution used in the example 10 at a rate such that the content ofsilicon oxide in a dried adhesive layer becomes 35% by weight.

The solution for forming an adhesive layer was applied by using a bakerapplicator onto a soda lime glass substrate with a thickness of 1 mm anda dimension of 7 cm×7 cm, and the coating material for forming aphotocatalyst layer was also applied by using bar coater onto the samesubstrate. Drying temperature was set to the same employed in theexamples described above.

The photocatalyst-carrying structure obtained was found to have veryhigh whole light transmittance.

Example 20 Use of Silica-alumina Sol

A photocalyst-carrying structure was prepared by using the samematerials and according to the same method as described in the example19 except replacing silica sol used in the example 19 with a mixed solsolution consisting of alumina sol manufactured by Nissan ChemicalIndustries Co., Ltd. and silica sol.

The photocatalyst-carrying structure obtained was found to have highadhesive property and photocatalytic activity.

Example 21

Coating According to Gravure Printing Method

By using gravure printing system, the solution for forming an adhesivelayer and the solution for forming a photocatalyst layer were appliedonto a polyester film (Trade name: Cosmoshine A4100) manufactured byToyobo Co., Ltd. at a speed of 10 m/min. and at dry zone temperature of130° C. such that the thickness of each layers become 3 μm,respectively. For the printing, a microgravure coater with a width of 70cm manufactured by Yasui Seiki Co., Ltd. was used.

The photocatalyst-carrying structure obtained was found to have veryhigh whole light transmittance of 95%.

Example 22 Coating According to Spraying Method

The solution for forming an adhesive layer and the solution for forminga photocatalyst layer used in the example 9 were sprayed onto asubstrate made of soda lime glass by using a spray gun (Type: WIDER 88,Manufactured by Iwata Tosoki Kogyo K.K.). Both solutions for formingadhesive layer and for photocatalyst layer were dried at 120° C. for 30minutes.

The photocatalyst-carrying structure obtained was found to have goodadhesive property and photocatalytic activity.

Example 23 Use of Epoxy-silicon Resin

A photocatalyst-carrying structure was prepared by using the samematerials and employing the same method as described in the example 12except replacing the polyester resin solution in xylene with methy ethylketone solution of epoxy resin containing 3% by weight of silicon.

The photocatalyst-carrying structure obtained was found to have goodadhesive property and photocatalytic activity.

The compositions and the results of performance tests on thephotocatalyst-carrying structures are presented in Table 3.

TABLE 3 Photocatalyst Layer Adhesive Layer Titanium PolysiloxaneColloidal Silica Resin Dioxide Z-1 Z-2 Z-3 Z-4 Carrier Type Content*¹Type Content*¹ Sol. Type Content*² Content*² Content*² Content*²Content*² Example-24 TA — — — — J-1 C-1 50 25 25 — — Example-25 TC — — —— J-2 C-1 50 25 25 — — Example-26 TC PS-1 20 — — J-1 C-1 25 65 — — 10Example-27 TC PS-1 20 — — J-2 C-1 25 60 — 15 — Example-28 TA PS-2 30 — —J-1 C-1 60 20 20 — — Example-29 TC PS-2 50 — — J-8 C-2 50 20 20 10 —Example-30 TC PS-2 20 — — J-8 C-2 70 20 10 — — Example-31 TA PS-3 20 — —J-6 C-2 25 40 35 — — Example-32 TE — — KS-1 20 J-3 C-1 30 40 20 — 10Example-33 TF — — KS-1 10 J-4 C-1 50 30 10 10 — Example-34 TD — — KS-230 J-3 C-1 20 40 10 30 — Example-35 TC — — KS-2 35 J-3 C-1 30 65  5 — —Photo- After Thick- Thick- cata- Adhesive Sunshine ness ness lyticProperty Adh. Weather Whole of of Activ. Bfr. Aft. Pro. Meter Test LightAdh. Pho. Aldehyde Dura- Dura- aft. Sur- Adh. Trans- Layr Layr Dec.bility bility B.W. face Pro- mittance (μ) (μ) Activ. Test Test TestState perty % Example-24 10 5 A 10 pt 8 pt 10 pt A 8 pt 72 Example-25 105 A 10  8 10 A 8 70 Example-26  5 3 A 10  8  8 A 8 80 Example-27 10 3 A10  6  8 A 6 75 Example-28  3 1 A 10 10 10 A 8 86 Example-29 0.5 0.3 C10  8  8 A 6 92 Example-30  5 3 A 10  6  8 A 6 80 Example-31  5 3 A 10 8  8 A 8 75 Example-32 10 7 A —*3 —*3 —*3 A —*3 —*4 Example-33  5 3 A10  8  8 A 8 —*4 Example-34  3 2 B 10  8 10 A 8 —*5 Example-35  3 3 A 1010 10 A 8 88 *1: Percent by weight as SiO₂ contained in a dried adhesivelayer. *2: Percent by weight of either a metal oxide gel or a metalhydroxide gel contained in a dried adhesive layer. *3: Since Cross-cutScotch tape test could not be employed, the surface of the sticking tapeside was observed by using a binocular, and it is noted that thephotocatalyst layer did not stick to the surface. *4: The determinationcould not be made due to the difference in configuration. *5: Thedetermination could not be made because of an opaque carrier.

Examples 24-25

In examples 24 and 25, a structure, wherein acryl-silicon resin is usedfor forming an adhesive layer, and a mixture prepared and composed with50% by weight of fine granule titanium dioxide P-25 (C-1), 25% by weightof silica sol represented at (Z-1) and 25% by weight of alumina solrepresented at (Z-2) are used for forming a photocatalyst layer, isdisclosed. The structures disclosed in these examples were found to havegood adhesive property as well as good durability and resistant propertyunder accelerated weathering condition.

Examples 26-31

In examples 26 through 31, a structure, wherein a resin containingpolysiloxane was used for forming an adhesive layer, and for forming aphotocatalyst layer, fine granule titanium dioxide (C-1) was used inexamples 26 through 28 while titania sol (C-2) was used in examples 29through 31, and the type and the quantity of a sol for forming acompoundable gel were changed, is disclosed. The structures prepared inthese examples were found to have good photocatalytic activity as wellas good adhesive property, durability and resistant property againstaccelerated weathering tests following to receiving boiling water test.

The resins introduced with polysiloxane, such as acryl-silicon resin(examples 26, 27 and 28) and epoxy-silicon resin (examples 29 and 30),were found to have good adhesive property, durability and resistanceagainst accelerated weathering. Also, acryl resin introduced withpolysiloxane (example 31) was found to have good properties.

Examples 32-35

In examples 32 and 33, a structure, wherein either polyethylen mesh orpolypropylene tube was used as the substrate was presented, however, thephotocatalyst-carrying structure having good photocatalytic activity,adhesive property and durability was not obtained.

In examples 32 through 35, structures, wherein a resin containingcolloidal silica was used for forming an adhesive layer, are disclosed,and photocatalytic activity, adhesive property, durability andresistance against accelerated weathering of such structures were foundto be excellent. In particular, when the structure is prepared withcolloidal silica in fine particles (KS-2) and the colloidal silica isintroduced into acryl-silicon resin emulsion (see examples 34 and 35),this type of structure was found to have very good properties.

In example 29, a structure, wherein a photocatalyst layer was formedwith a coating material prepared by dispersing titania sol containing12% by weight of titanium dioxide, silica gel (Trade name: CataloidSI-30, manufactured by Shokubai Kasei Co., Ltd.) and alumina sol-200manufactured by Nissan Chemical Industries Co., Ltd., adjusting the pHof the resulting mixture to 1.5 and adding a predetermined amount of asurfactant to the mixture, and the thickness of an adhesive layer and aphotocatalyst layer was made to 0.5 μm and 0.3 μm by dipping method,respectively, is disclosed. The structure provided with the layers asdescribed above was found to have good adhesive property and durabilityas well as high photocatalytic activity, nonethless of the thinthickness of the photocatalyst layer.

A structure with excellent physical property was also obtained even ifcontents in total of silica gel and alumina sol in a photocatalyst werereduced down to 30% by weight (see example 30).

Photocatalytic activity was determined again on the samples, which wereprepared in the examples 24 through 35 and were allowed to a durabilitytest under black light at a high temperature and high humidity, dippingtest in boiling water and accelerated weathering test by using Sunshinecarbon arc weather meter, according to the same method as describedabove, namely based on the decomposed amount of acetaldehyde by light.As a result, it is found that all samples showed equivalent decomposingactivity to the initial decomposed-amount of acetaldehyde, and it isfound that the samples have fully kept their intial photocatalyticactivity.

The compositions and performance test results on thephotocatalyst-carrying structures disclosed in the examples 36 through53 are presented in Tables 4 and 5.

TABLE 4 Photo- Adhe- cata- sive lyst Photocatalyst Layer Layer LayerAdhesive Layer Titanium Thick- Thick- Resin Dioxide Z-1 Z-2 Z-3 Z-5 Z-6ness ness Carrier Type Content*1 Sol. Type Content*1 Content*2 Content*2Content*2 Content*2 Content*2 (μ) (μ) Example-36 TA — — J-1 C-1 50 40 —— 10 — 10  6 Example-37 TB — — J-1 C-1 40 40 — — 20 — 10  6 Example-38TA PS-1 15 J-1 C-1 40 10 — — 10 — 7 7 Example-39 TB PS-1 30 J-1 C-1 25 —— — 50 — 7 3 Example-40 TC PS-1 45 J-2 C-1 20 30 10 10 30 — 3 3Example-41 TB PS-1 10 J-2 C-1 25 50 — 10 15 — 5 3 Example-42 TA PS-2 20J-2 C-1 40 30 10 — 10 10 3 1 Example-43 TB PS-2 30 J-8 C-1 40 20 10 — 2010   0.6   0.2 Example-44 TD PS-2 45 J-7 C-2 50 20 — 10 20 — 5 3Example-45 TE PS-2 10 J-1 C-2 50 20 10 — — 20 6 6 Example-46 TB PS-2 20J-8 C-2 25 30 25 — — 20 5 3 Example-47 TB PS-3 30 J-6 C-2 60 10 10 — 15 5 3 3 Example-48 TA KS-1 10 J-3 C-1 30 20 10 — 35  5 10  6 Example-49TB KS-1 20 J-4 C-1 50 30 10 —  5  5 5 3 Example-50 TC KS-2 30 J-3 C-1 2030 10 — 30 10 5 3 Example-51 TB KS-2 40 J-4 C-2 30 40 20 — 10 — 3 3Example-52 TD KS-2 20 J-3 C-2 60 20 — — 20 — 5 3 Example-53 TE KS-2 30J-3 C-2 20 40 — 10 30 — 5 2 Reference TA — — — C-1 40 30 10 — 20 — 10 10  Example-5 Reference TB PS-1 70 J-1 C-1 40 30 10 — 20 — 10  6Example-6 Reference TA KS-1 50 J-3 C-1 40 30 10 — 20 — 10  6 Example-7Reference TB PS-1 30 J-1 C-1 45 30 20 —  5 — 7 3 Example-8 *1: % byweight as SiO₂ in a dried adhesive layer. *2: % by weight of titaniumdioxide and either a metal oxide gel or a metal hydroxide gel in totalin a dried photocatalyst layer.

TABLE 5 Adhesive Adhesive Sunshine Property Property Weather MeterBefore After After State of Adhesive Whole Dura- Dura- Boiling SurfaceProperty Light Photocatalytic bility bility Water After After Transmit-Activity Test Test Test Test Test tance (%) Example-36 A 10 pt. 8 pt. 10pt. A 8 pt. 68 Example-37 A 10  8 10 A 8 65 Example-38 A 10 10  8 A 8 63Example-39 B 10 10  8 A 8 75 Example-40 B 10 10 10 A 8 —*5 Example-41 B10  8  8 A 6 71 Example-42 C 10 10 10 A 8 82 Example-43 C 10  8  8 A 687 Example-44 B —*3 —*3 —*3 A —*3 —*4 Example-45 A 10 10  8 A 8 —*4Example-46 B 10  8 10 A 6 75 Example-47 B 10  8  8 A 6 70 Example-48 A10  8  8 A 8 66 Example-49 B 10  8  8 A 8 77 Example-50 B 10  8 10 A 8—*5 Example-51 B 10  8 10 A 8 83 Example-52 B —*3 —*3 —*3 A —*3 —*4Example-53 C 10  8 10 A 6 —*4 Reference A  2  2  0 C 0 54 Example-5Reference A  4  2  2 C 2 52 Example-6 Reference A  4  2  2 C 2 48Example-7 Reference B  4  4  2 C 4 51 Example-8 *3: Since cross-cutScotch tape test cannot be employed, the observation was made on thesurface of the sticking tape side by using binocular. As a result, aphotocatalyst layer has not been sticked. *4: The determination of thelight transmittance could not be made due to its abmormal configuration.*5: The determination of the light transmittance could not be madebecause of an opaque carrier.

In reference example 5, a structure, wherein a photocatalyst layer iscarried but no adhesive layer is carried thereon, is disclosed. In thiscase, the photocatalyst layer has no adhesive property and is easilydefloiated from the substrate, and it is obserbed that the surface ofpolyester film after receiving a durability test was deteriorated due tophotocatalytic action, and the presence of holes and cracks wereobserved on the film through a binocular.

In examples 36 and 37, a structure, wherein acryl-silicon resin was usedfor forming an adhesive layer and a complex prepared and composed with40-50% by weight of fine granule titanium dioxide P-25 manufactured byNihon Aerozil Co., Ltd., 40% by weight of silica sol represented at(Z-1) and 10-20% by weight of acryl-silicon resin emulsion was used forforming a photocatalyst layer, is disclosed. The structures disclosed inthese examples were found to have good adhesive property after receivingboiling test as well as good durability and resistance againstaccelerated weathering.

In examples 38 through 42, a structure, wherein acryl-silicon resincontaining polysiloxane was used for forming an adhesive layer and thesame photocatalyst powder as the one used in the example 36 was used forforming a photocatalyst layer, and type and content of a sol for formingcompoundable gel were changed, is disclosed. The structures prepared inthese examples were found to have good photocatalytic activity as wellas good adhesive property, durability and resistance against acceleratedweathering after receiving boiling water test. In both cases that theresin whereto polysiloxane was introduced was acryl-silicon resincontaining 3% by weight of silicon (examples 38 and 39) or acryl-siliconresin containing 10% by weight of silicon (examples 40, 41 and 42), theadhesive property, durability and resistance against acceleratedweathering of the structures were found to be excellent.

In examples 44 and 45, a structure, wherein an adhesive layer and aphotocatalyst layer were carried on either polyethylene mesh orpolypropylene tube, is disclosed, and the structures prepared in theseexamples were found to have good photocatalytic activity, adhesiveproperty and durability.

Such good physical properties were also observed for the structureswherein the resin whereto polysiloxane was introduced is any ofepoxy-silicon resin (examples 43 and 46), polyester resin (example 44)and acryl resin (example 47).

However, as shown in reference example 6, a photocatalyst layer lost itsadhesive property and was defoliated, when the content of polysiloxanein an adhesive layer became 70% by weight even though acryl-siliconresin containing polysiloxane was used for the adhesive layer.

In examples 48 through 53, a structure, wherein a resin containingcolloidal silica was used for forming an adhesive layer, and thestructures prepared in these examples were found to have goodphotocatalytic activity, adhesive property after receiving boiling watertest, durability and resistance against accelerated weathering. Inparticular, the structures, wherein colloidal silica having fineparticle diameter (KS-2) and acryl-silicon emulsion resin introducedwith said colloidal silica were used (examples 50 through 53), werefound to have excellent physical properties.

Whereas, the adhesive property and the durability of the structure,wherein the content of colloidal silica in the adhesive layer wasincreased to 50% by weight (reference example 7), was found to beradically deteriorated.

In examples 44 through 47, a structure, wherein an adhesive layer and aphotocatalyst layer were provided by bar coat method, and a coatingmaterial for forming the phohtocatalyst layer was prepared by dispersingtitania sol acidified with nitric acid and containing 12% by weight oftitanium dioxide, which was replaced from fine granule titanium dioxide(P-25) manufactured by Nihon Aerozil Co., Ltd., silica gel (Trade name:Cataloid SI-30) manufactured by Shokubai Kasei Co., Ltd. and eitheralumina sol-200 manufactured by Nissan Chemical Industries Co., Ltd. orzirconia sol manufactured by Nippon Soda Co., Ltd., adjusting the pH ofthe resulting mixture to 1.5, and adding a predetermined amount of asurfactant to the said mixture. The structures prepared in theseexamples were found to have good adhesive property and durability aswell as high photocatalytic activity even though the thickness of thephotocatalytic layer is relatively thin.

In example 47, a structure having good physical properties was obtainedeven decreasing the content in total of acryl-silicon resin emulsion andsilane coupler in a photocatalyst layer down to 20% by weight, however,in reference example 8, adhesive property and durability were radicallydecreased when such content in total was reduced down to 5% by weighteven adding acryl-silicon resin emulsion to the photocatalyst layer.

The samples obtained in the examples 36 through 53 and allowed to all ofa durability test under irradiation of black light at a high temperatureand high humidity, dipping test in boiling water, and acceleratedweathering test using Sunshine carbon arc weather meter, were checkedagain for their photocatalytic activity according to the same methodemployed at the start of this test based on decomposed-amount ofacetaldehyde by light, and it is found that all samples showed the samedecomposed-amount of acetaldehyde as the ones obtained at the start ofthis test and have maintained yet the initial photocatalytic activitywith a full capacity.

Example 54

According to the method employed in the example 42, a sample of atitanium dioxide photocatalyst-carrying strycture was prepared, and theantimicrobial activity of the sample was evaluated.

As a result, it was found that the survival rate of colon bacillus onthe sample, which was left in a dark place, was 92%, 91% and 91% after1, 2 and 3 hours, respectivily, whereas such rate on the other sample,which was exposed to black light, was 52%, 22% and 11% after 1, 2 and 3hours, respectively. The antimicrobial activity was noted even on thesample which was placed under a flourescent lamp, and the survival rateof colon bacillus was 76%, 54% and 22% after 1, 2 and 3 hours,respectively, and those ratios were higher than the ones of the samplesleft in a dark place.

As a silicon compound used for a coating material of a photocatalyst,the followings were used.

(S-1) 5% by weight ethanol solution of tetraethoxy silane (Super ReagentGrade, Manufactured by Wako Pure Chemical Co., Ltd.).

(S-2) 5% by weight ethanol solution of tetramethoxy silane (Manufacturedby Shinetsu Chemical Industry Co., Ltd.

(S-3) 5% by weight ethanol solution of methyltriethoxy silane (SuperReagent Grade, Manufactured by Wako Pure Chemical Co., Ltd.).

(S-4) 5% by weight ethanol solution of tri(β-methoxyethoxy)vinyl silane(Manufactured by Nihon Unikar Co., Ltd., Trade name: A-172).

To a sol solution and a silicon compound solution represented at (Z-1)through (Z-3), either titanium dioxide powder or sol was dispersed as aphotocatalyst together with either water or a mixed solvent of water andethanol while adjusting the pH of the mixture to an appropriate valueranging from 1.5 to 9 depending upon the type of raw materials andadditives, and was further added with a prefixed amount of a surfactantto thereby obtain a coating material for forming a photocatalyst layer.The content of the components contained in the said coating material andviscosity and sedimentation state of the particles just after thepreparation of the coating material and after 90 days from the sealingare presented in Table 6.

TABLE 6 Silicon Photocatalyst Metal Dioxide Compound At Start After 90days Content*1 Content*1 Content*1 Viscosity Sedimentation ViscositySedimentation Type wt % Type wt % Type wt % cP % cP % Example 55 C-1 20Z-1 20 S-1 1 31 100 43 90 56 C-1 10 Z-1 20 S-1 1 14 ″ 16 85 57 C-1 5 Z-15 S-1 0.2 3 ″ 4 95 58 C-2 30 Z-1 10 S-1 2 33 ″ 37 100 59 C-2 10 Z-1 10S-3 0.1 7 ″ 9 100 Z-2 0.3 60 C-2 2 Z-1 2 S-3 0.01 1 ″ 1 100 Z-2 0.05 61C-1 0.5 Z-1 0.5 S-2 0.02 1 ″ 1 95 62 C-1 0.1 Z-1 0.1 S-2 0.002 1 ″ 1 9563 C-1 3 Z-1 6 S-1 0.2 2 ″ 2 90 C-2 3 Z-3 0.2 64 C-3 5 Z-1 7 S-4 0.2 3 ″5 95 65 C-3 1 Z-1 2 S-3 0.04 2 ″ 2 100 66 C-3 0.2 Z-1 0.2 S-1 0.01 1 ″ 1100 Reference Example 9 C-1 5 Z-1 5 — 3 100 12 45 10 C-2 30 Z-1 10 — 33″ 430 55 11 C-2 10 Z-1 10 — 7 ″ 23 65 Z-2 0.3 — 12 C-3 5 Z-1 7 — 3 ″ 950 13 C-3 1 Z-1 2 — 2 ″ 3 60 Note: Sedimentation of particles wasindicated with a ratio of sedimentation volume relative to the wholevolume of the coating solution. *1: The content is indicated withpercent by weight based on the weight of dried coating solution.

In examples 55 through 57, a photocatalyst-carrying structure, whereintitanium dioxide powder (P-25) was used as a photocatalyst, isrespectibely disclosed. By the addition of a small amount of a siliconcompound, the stability after 90 days of the coating material of aphtocatalyst was improved very much.

In examples 58 through 60, titania sol acidified with nitric acid wasused as a photocatalyst, silica gel and alumina sol were jointly used asthe compoundable metal oxide sol, and methyltriethoxy silane was used asa silicon compound in examples 59 and 60. By employing this method,remarkable improvement in the resistant property to boiling water,particularly resistance to boiling water in tap water, of the structureformed with a film thereon by applying such coating material, wasachieved. In examples 61 and 62, a photocatalyst-carrying structure,wherein tetramethoxy silane was used as a silicon compound, and it isnoted that this structure showed an advantage that it can keep thestability of the coating material, even the amount of tetramethoxysilane to add was so small.

In example 63, a photocatalyst-carrying structure, wherein powdertitanium dioxide (P-25) and titania sol were jointly used for thephotocatalyst, and silica sol and zirconia sol were jointly used for acompoundable metal oxide sol, is provided, whereas a coating materialhaving good stability and sedimental property was obtained by addingtetramethoxy silane in the solution.

In examples 64 through 66, a photocatalyst-carrying structure, wherein acoating material for forming a photocatalyst layer was prepared bychanging the type of silicon compounds, and each coating materialprepared in these examples were found to be stable at any prefixedamount to add.

On the contrary, in examples 9 through 13, since no silicon compound wasadded to a coating material, the viscosity of the coating material wasdrastically increased after 90 days, and sedimentation of particles wascetainly resulted in, and therefore, it was difficult to control thecondition for forming films when such coating material was used, and itwas not feasible to obtain a photocatalyst-carrying structure havingstable quality.

Examples 67 through 71

By using the coating materials prepared in the examples 55 through 59,photocatalyst-carrying structures were prepared by using the substratesrecited in the following. The materials used for the substrate were asfollows.

(SA) Primer-treated polyester film

(SB) Soda lime-made galss plate

(SC) Metal aluminium plate

(SD) High-density polyethylene mesh (Tnickness of fiber: 0.2 mm, meshsize: 0.6 mm)

(SE) Polypropylene-made mesh (Inner diameter: 30 mm, Outer diameter: 36mm)

The adhesive layer was formed by dipping method when the thicknessthereof was 2 μm or less or the configuration of the substrate was otherthan plate-shaped, or by a method using a baker applicator when thesubstrate was plate-sshaped and the thickness thereof was formed to 2 μmor more. Temperature used for drying the adhesive layer was 80° C. onlywhen the material of the substrate was (SD) or (SE), and it was at 120°C. in all other cases. The photocatalyst layer was formed by dippingmethod when the thickness thereof was 2 μm or less or the configurationof the substrate was other than plate-shaped, or by a method using a barcoator when the substrate was plate-shaped and the thickness thereof wasformed to 2 μm or more. Drying of the photocatalyst layer was performedat the same temperature as the one for drying the adhesive layer.Hereunder, physical properties of the photocatalyst-carrying structuresprepared in the examples and the reference examples, wherein type andcontent of the materials described above, the thickness of a filmcoated, method to form films, etc. were each modified, are presented inTables 7 and 8.

TABLE 7 Thickness Thickness of Coating Solution Coating Solution for ofPhoto- for Adhesive Layer Photocatalyst Layer Adhesive catalyst ResinTiO₂ Z-1 Z-2 Layer Layer Example Carrier Type Content*1 Sol. TypeContent*2 Content*2 Content*2 (μ) (μ) Example-67 SA PS-1 10 J-1 C-1 2020 — 3 3 Example-68 SA PS-1  5 J-1 C-1  2  0 — 1 3 Example-69 SC PS-1 20J-2 C-1  5  5 — 4 2 Example-70 SD PS-2 20 J-2 C-2 30 10 — 5 3 Example-71SE PS-2 30 J-2 C-2 10 10 0.3 4 2 *1: Concentration of solid component ofthe resin in the coating solution. *2: Concentration of solid componentin the coating solution.

TABLE 8 Adhesive Property Sunshine Weather Whole After Meter lightBefore After Boiling Surface Adh. Pro. Transmit- PhotocatalyticDurability Durability Water State after tance Example Activity Test TestTest aft. Test Test (%) Example-67 A 10 10 —*6 A 10 63 Example-68 A 1010 —*6 A 10 75 Example-69 B 10 10 —*6 A 10 —*5 Example-70 B 10 10 —*6 A—*3 —*4 Example-71 B 10 10 10 A 10 82 *3: Since cross-cut Scotch tapetest could not be employed, the surface of the sticking tape wasobserved by using a binocular, however no adhesion of the photocatalystlayer was observed. *4: The determination could not be made due to thedifference in configuration. *5: The determination could not be madebecause of an opaque carrier. *6: No evaluation has been made.

For the samples obtained in the examples 67 through 71 and allowed toblack light resistance test under a high temperature and high humiduty,dipping test in boiling water and accelerated weathering test by usingSunshine carbon arc weather meter, photocatalytic activity wasrespectively determined again beased on decomposed-amount ofacetaldehyde by light that was the method employed for suchdetermination before starting the tests described above. From the resultthat the same level of decomposed-amount of acetaldehyde as the onesobtained before allowing the samples to such tests above was obtained,it is demonstrated that the original photocatalytic activity has beenfully maintained in the structures.

Example 72

A photocatalyst-carrying structure comprising titanium dioxide wasprepared according to the same method as described in the example 67,and an antimicrobial test was carried out for the structure according tothe method described above. The survival rate of colon bacillus on thestructure with no radiation of light was 92%, 91% and 91% after 1, 2 and3 hours, respectively, whereas the survival rate on the structure whichwas exposed to radiation of black light was 52%, 29% and 11% after 1, 2and 3 hours, respectively. Further, the survival rate of colon bacilluson the structure exposed to radiation of flourescent lamp was 76%, 54%and 22% after 1, 2 and 3 hours, respectively, which showed higherantimicrobial activity than the structure placed in a dark site.

Example 73 Films Processed with Sticker

A solution for forming an adhesive layer was prepared by mixing 30% byweight of polysiloxane (Manufactured by Colcoat Co., Ltd., Trade name:Methyl Silicate 51) based on the weight of acryl-silicon resin and 5% byweight of a curing agent (silane coupler) based on the weight ofacryl-silicon resin to a mixed solution of xylene and isopropanol(mixing ratio, 50:50) containing 25% by weight of acryl-silicon resinwhich contains 3% by weight of silicon, and was diluted with methylethyl ketone to adjust the concentration to 10% by weight on the solidcomponent basis.

The diluted solution obtained was applied by gravure printing onto apolyester film (Trade name: Cosmoshine 50 μm) A4100 manufactured byToyobo Co., Ltd. so as to form a film having a thickness of 1 μm afterdrying by using a microgravure coater (width: 70 cm) manufactured byYasui Seiki Co., Ltd. at a speed of 15 m/sec and at dry zone temperatureof 13.

The polyester film whereto an adhesive layer was formed was then appliedwith a coating material for forming a photocatalyst layer, which wasprepared by dispersing titania sol acidified with nitric acid containing20% by weight of titanium dioxide as a photocatalyst into silica solacidified with nitric acid containing 20% of silicon oxide in thepresence of a surfactant, and then diluting the dispersion with amixture of ion-exchanged water and ethanol (mixing ratio, 50:50) to aconcentration of 10% by weight on the solid components basis, by gravureprinting same as for the adhesive layer to thereby obtain a polyesterfilm formed with a photocatalyst layer having dried-thickness of 1 μm.

Next, to the surface of the photocatalyst-carrying structure compringpolyester film whereto a photocatalyst was not applied, a solutionprepared by adding 5% by weight on the solid basis of a coating agentfor blocking thermic rays, STS-500, manufactured by Sumitomo OsakaCement Co., Ltd. into a commercially-available sticker was applied byemploying gravure printing method. The film applied with the sticker waswinded while laminating the film with polyethylene film (Pyrene film-OT20 μm) P-2161, manufactured by Toyobo Co., Ltd. at a process for dryingand winding at the drying zone in the gravure printer, to therebyproviding a sticking film.

This kind of films can be used for a sticking film for window glass forautomobiles, home window glass, and window glass for medical facilities,and they are advantageously characterized from their properties, such asantimicrobial activity, soiling resistant property and deodorantproperty, as well as scattering-preventive films at breaking of glass.

Example 74 Plate Glass

To a plate glass made of soda lime having thickness of 1 mm and cut intoa piece with a dimension of 5 cm×5 cm, a solution prepared by mixing 30%by weight of polysiloxane (methyl silicate 51, manufactured by ColcoatCo., Ltd.) based on the weight of acryl-silicon resin into a mixedsolution of xylene and isopropanol (mixing ratio, 50:50) containing 25%by weight of acryl-silicon resin which contains 3% by weight of silicon,was applied by using No. 7 bar coater and was dried at 100° C. for 60min. to form an adhesive layer. After allowing the plate glass tocooling under an ambient temperature, a coating material for forming aphotocatalyst layer was prepared by dispersing titania sol acidifiedwith nitric acid containing 20% by weight of titanium dioxide intosilica sol acidified with nitric acid containing 20% by weight ofsilicon oxide in the presence of a surfactant. The solution obtained wasthen applied onto the adhesive layer described above by using No. 7 barcoater as well, and was then dried for 60 min. at 100° C. to therebyobtain a photocatalyst-carrying glass plate (Sample No. 1).

Example 75 Glass Fiber Papers

The solution for forming an adhesive layer used in the example 74 wasdiluted with xylene-propanol solution (mixing ratio, 50:50) to obtain aconcentration of 5% by weight on the solid component basis. A glassfiber paper, SAS-030 (weight: 30 g/m²) manufactured by Oribest Co., Ltd.was dipped in the diluted solution prepared as described above and wasthen pulled out, allowed to stand and dried at 100° C. for 120 min. toform an adhesive layer on the surface of the said glass fiber paper.Then, the glass fiber paper whereto the adhesive layer was formed wasdipped into a solution prepared by diluting the coating material forforming a photocatalyst layer used in the example 74 with ion-exchangedwater to a concentration of 10% by weight, and was pulled out and driedat 100° C. for 120 min. to obtain a photocatalyst-carrying glass fiberpaper (Sample No. 2).

Example 76 Lens for Glasses

An adhesive layer was formed onto lens for glasses, PC pointal coatTC(+)1.00S 0.00 65 mmΦ manufactured by Nikon Corporation, by applying asolution prepared by admixing polysiloxane (Methyl Silicate 51manufactured by Colcoat Co., Ltd.) 20% by weight based on the weight ofacryl-silicon resin into a mixed solution of xylene and isopropanol(mixing ratio, 50:50) containing 10% by weight of acryl-silicon resinwhich contains 3% by weight of silicon onto the lens according todipping method as described in the example 75, and the coated-lens weredried at 100° C. for 20 min. After cooling the lens at an ambienttemperature, a coating material for forming a photocatalyst layer wasprepared by dispersing titania sol as a photocatalyst acidified withnitric acid and containing 5% by weight of titanium dioxide into silicasol acidified with nitric acid and containing 5% silicon oxide in thepresence of a surfactant. Using this coating material for photocatalystlayer and employing dipping method similarly, a photocatalyst layer wasformed by coating the said coating material onto the surface of saidadhesive layer and was dried at 100° C. for 20 min. to obtainphotocatalyst-carrying lens for glasses (Sample No. 3).

Example 77 Wall Papers made of Poly(Vinyl Chloride)

A solution prepared by mixing polysiloxane (Methyl Silicate 51manufactured by Colcoat Co., Ltd.) 30% by weight based on the weight ofacryl-silicon resin into a mixed solution of xylene and isopropanol(mixing ratio, 50:50) containing 25% by weight of acryl-silicon resinwhich contains 3% by weight of silicon was applied onto a wall papermade of poly(vinyl chloride)(SG 5328, manufactured by Sangetsu Co.,Ltd.) cut into a piece with a demension of 5 ccm×5 cm and a thickness of1 mm by using a bar coater No. 7, and the applied-paper was then driedat 100° C. for 20 min. to obtain an adhesive layer. After cooling thepaper at an ambient temperature, a coating material for forming aphotocatalyst layer was prepared by dispersing titania sol as aphotocatalyst acidified with nitric acid and containing 20% by weight oftitanium dioxide into silica sol acidified with nitric acid andcontaining 20% silicon oxide in the presence of a surfactant. Applyingthis solution onto the surface of the adhesive layer by using a barcoater No. 7, and the paper coated was dried at 100° C. for 20 min. toobtain a photocatalyst-carrying wall paper (Sample No. 4).

Example 78 Polyester Films

The solution for forming an adhesive layer used in the example 77 wasdiluted with a mixed solution of xylene and isopropanol (mixing ratio,50:50) to adjust the concentration of the mixture to 25% by weight onthe solid components basis. The diluted solution was then applied bygravure printing at a speed of 10 m/min. and at dry zone temperature of130° C. onto a polyester film (Cosmoshine) A4100 manufactured by ToyoboCo., Ltd. by using a microgravure coater (width: 70 cm) manufactured byYasui Seiki Co., Ltd. to form a film with a thickness after drying of 3μm. Then, the polyester film formed with an adhesive layer was furtherapplied with the coating material for forming a photocatalyst layer usedin the example 77 according to gravure printing to thereby obtain aphotocatalyst-carrying polyester film provided with a photocatalystlayer having a thickness after drying of 3 μm (Sample No. 5).

Example 79 Protective Filters for Personal Computers

A solution for forming an adhesive layer was prepared by mixingpolysiloxane (Methyl Silicate 51 manufactured by Colcoat Co., Ltd.) 30%by weight on the solid component basis relative to the weight ofacryl-silicon resin into a xylene solution containing 20% by weight ofacryl-silicon resin which contains 20% by weight of silicon and wasdiluted with an isopropanol solution to adjust the concentration to 20%by weight on the solid component basis. Then, the solution was appliedby dipping onto VDT filter, E-filter III, manufactured by Toray Co.,Ltd., and the filter coated was then dried at 100° C. for 20 min. toform an adhesive layer on the surface of the filter. Subsequently, theVDT protective filter formed with adhesive layer was further allowed todipping process in a solution prepared by diluting the coating materialused in the example 77 with ion-exchanged water to the extent that thecontent of solid component in the coating material to be 10% by weight,pulled out therefrom and dried at 100° C. for 20 min. to obtain aphotocatalyst-carrying VDT filter (Sample No. 6).

Example 80 Telephone Set Cases

The solution for forming an adhesive layer used in the example 77 wasdiluted with a mixed solution of xylene and isopropanol (mixing ratio,50:50) to adjust the concentration of the solution to 20% by weight onthe solid component basis. The diluted-solution was applied by sprayingto a case for a telephone set (Type: HIT-1, Manufactured by HitachiSeisakusho Co., Ltd.) by using a spray gun (Type: WIDER 88, Manufacturedby Iwata Tosoki Kogyo Co., Ltd). After drying the sprayed-case at 100°C. for 20 min., a coating material for forming a photocatalyst layerused in the example 1 was adjusted by dilution with ion-exchanged waterto a concentration of 8% by weight on the solid component basis, and thediluted-coating material was applied by spraying as described above.After drying the case at 100° C. for 20 min., a photocatalyst-carryingtelephone set case was obtained (Sample No. 7).

Example 81 Lens for Glasses

An adhesive layer was formed onto lens for glasses, NL70HCCTc(+) 1.00S0.00 (70 mmΦ) manufactured by Nikon Corporation, by applying a solutionprepared by admixing polysiloxane (Methyl Silicate 51 manufactured byColcoat Co., Ltd.) 20% by weight based on the weight of acryl-siliconresin into a mixed solution of xylene and isopropanol (mixing ratio,50:50) containing 10% by weight of acryl-silicon resin which contains 3%by weight of silicon onto the lens according to dipping method asdescribed in the example 79, and the coated-lens were dried at 100° C.for 20 min. After cooling the lens at an ambient temperature, a coatingmaterial for forming a photocatalyst layer, which was prepared bydispersing titania sol as a photocatalyst acidified with nitric acid andcontaining 15% by weight of titanium dioxide into silica sol acidifiedwith nitric acid and containing 15% silicon oxide in the presence of asurfactant, was applied onto the lens to form a photocatalyst layer.Using this solution for photocatalyst layer and employing the samedipping method, a photocatalyst layer was formed by coating the solutiononto the surface of said adhesive layer and was dried at 100° C. for 20min. to obtain photocatalyst-carrying lens for glasses (Sample No. 8).

Example 82 Curtains

Textile fabrics for curtains, trade name “Hospia” (for school andhospital use) manufactured by Kawashima Orimono Co., Ltd. were cut intoa piece with a dimension of 7 cm×7 cm, and the pieces were dipped into asolution prepared by mixing polysiloxane (Methyl Silicate 51manufactured by Colcoat Co., Ltd.) 20% by weight on the solid componentbasis relative to the weight of acryl-silicon resin into a mixedsolution of xylene and isopropanol (mixing ratio, 50:50) containing 15%by weight of epoxy-silicon resin which contains 3% by weight of silicon,pulled out therefrom and dried at 80° C. for 120 min. After cooling thefabrics at an ambient temperature, the textile fabrics whereto anadhesive layer was formed thereon was dipped into a coating material forforming photocatalyst layer which was prepared by dispersing titania solproduced by Ammonia Alkali containing 10% by weight of titanium dioxideinto silica sol containing 10% by weight of silicon oxide in thepresence of a surfactant, pulled out therefrom and dried at 80° C. for120 min. to obtain a photocatalyst-carrying textile fabric for curtainuse (Sample No. 9).

Example 83 Nonwoven Fabrics

Non-bleached nonwoven fabric made of cotton (Trade name: Orcos,Manufactured by Nisshinbo Co., Ltd.) was cut into pieces each having adimension of 7 cm×7 cm, and each piece was sprayed with a solutionprepared by mixing polysiloxane (Methyl Silicate 51 manufactured byColcoat Co., Ltd.) 30% by weight based on the weight of acryl-sliconresin into a mixed solution of xylene and isopropanol (mixing ratio,50:50) containing 25% by weight of acryl-silicon resin which contains 3%by weight of silicon by using a spray gun (Type: WIDER 88, Manufacturedby Iwata Tosoki Kogyo Co., Ltd.). After drying the sprayed fabric at100° C. for 30 min., the solution for forming a photocatalyst layer usedin the example 82 was applied to the said fabric, and the applied fabricwas then dried at 100° C. for 30 min. to obtain a photocatalyst-carryingcotton nonwoven fabric suitable for surgical gowns, tableclothes, coversfor a toilet seat, shoji papers, covering sheets for seedlings, foodpackaging materials, etc.

Example 84 Printed Polyester Cloth Fabrics for Umbrella

Using commercially available printed polyester cloth fabrics forumbrella use as a substrate, an adhesive layer and a photocatalyst layerwere coated thereon according to the same method disclosed in theexample 83. The photocatalyst-carrying printed polyester cloth fabricobtained here was found to have almost no difference in patterns andfeeling from normal cloth fabrics (Sample No. 11).

Example 85 Wall Papers (Woven Cloth)

Using a plain woven cloth, SG 6758, manufactured by Sangetsu Co., Ltd.as a substrate, an adhesive layer and a photocatalyst layer were formedonto the cloth according to the method disclosed in the example 83. Thephotocatalyst-carrying woven cloth wall paper did not give bad influenceon the quality of the woven cloth (Sample No. 12).

Example 86 Aluminum Sash

A solution prepared by mixing polysiloxane (Methyl Silicate 51,manufactured by Colcoat Co., Ltd.) 30% by weight based on the weight ofacryl-silicon resin into a mixed solution of xylene and isopropanol(mixing ratio, 50:50) containing 25% by weight of acryl-silicon resinwhich contains 3% by weight of silicon was applied onto a aluminum sashplate cut into a piece with a dimension of 7 cm×7 cm by using a barcoater No. 7 and the aluminum sash plate was dried at 100° C. for 60min. to form an adhesive layer on the plate. After cooling the plate atan ambient temperature, a coating material for forming a photocatalystlayer was prepared by dispersing titania sol acidified with nitric acidcontaining 20% by weight of titanium dioxide into silica sol acidifiedwith nitric acid containing 20% by weight of silicon oxide in thepresence of a surfactant. The coating material was then applied onto thesurface of the adhesive layer described above by using a bar coater No.7, and the applied plate was dried at 130° C. for 10 min. to obtain aphotocatalyst-carrying aluminum plate (Sample No. 13).

Example 87 Stainless Steel Plates

The solution for forming an adhesive layer used in the example 86 wasadjusted by dilution with a mixed solution of xylene and isopropanol(mixing ratio, 50:50) to a concentration of 5% by weight on the solidcompomnent basis. A stainless steel plate made of SUS 316 (Thickness:0.2 mm) cut into a piece with a dimension of 7 cm×7 cm was dipped intothe solution described above, pulled out therefrom and dried at 120° C.for 20 min. to form an adhesive layer on the surface of the stainlesssteel plate. Then, the stainless steel plate whereto an adhesive layerwas formed was dipped into a solution prepared by adjusting theconcentration of the coating material for a photocatalyst layer used inthe example 86 with ion-exchanged water to a concentratiob of 10% byweight, pulled out therefrom and dried at 120° C. for 20 min. to obtaina photocatalyst-carrying stainless steel plate (Sample No. 14).

Example 88 Tin Plates

A tin plate having a thickness of 1 mm cut into a piece with a dimensionof 7 cm×7 cm was dipped into a solution prepared by mixing polysiloxane(Methyl Silicate 51, manufactured by Colcoat Co., Ltd.) 30% by weightbased on the weight of acryl-silicon resin into 20% by weight of xylenesolution of acryl-silicon resin which contains 20% by weight of siliconand then diluting the mixture with isopropanol solution up to aconcentration of 20% by weight on the solid component basis, pulled outtherefrom and dried at 100° C. for 60 min. to form an adhesive layer onthe tin plate. The tin plate on which an adhesive layer was formed wasthen dipped into a solution prepared by adjusting the coating materialfor forming a photocatalyst layer used in the example 86 by dilutionwith ion-exchanged water to a concentration of 10% by weight, pulled outfrom the solution and dried at 100° C. for 60 min, to obtain aphotocatalyst-carrying tin plate (Sample No. 15).

Example 89 Blinds

After removing a slat having a width of 800 mm and a height of 700 mm ofa blind, “Silky Curtain” (15 mm slat width type) T-12 (white),manufactured by Tachikawa Blind Industry Co., Ltd., a solution preparedby mixing polysiloxane (Methyl Silicate 51, manufactured by Colcoat Co.,Ltd.) of 30% by weight based on the weight of acryl-silicon resin into amixed solution of xylene and isopropanol (mixing ratio, 50:50)containing 25% by weight of acryl-silicon resin which comprises 3% byweight of silicon was apllied by spraying by using a spray gun, WIDER88, manufactured by Iwata Tosoki Kogyo Co., Ltd. After drying thesprayed-blind at 120° C. for 20 min., the blind was further applied byspraying with a solution prepared by diluting the coating material forforming a photocatalyst layer used in the example 86 with ion-exchangedwater to a concentration of 8% by weight on the solid component basis(Sample No. 16).

Example 90 Printed Plywood

A printed plywood, Neowood, having a thickness of 2.5 mm and cut into apiece with a dimension of 7 cm×7 cm, manufactured by Eidai Sangyo Co.,Ltd. was applied with a solution prepared by mixing polysiloxane (MethylSilicate 51, manufactured by Colcoat Co., Ltd.) 30% by weight based onthe weight of acryl-silicon resin into a mixed solution of xylene andisopropanol (mixing ratio, 50:50) containing 25% by weight ofacryl-silicon resin which comprises 3% by weight of silicon by using abar coater No. 7 and was then dried at 100° C. for 30 min. to form anadhesive layer on the printed plywood. After cooling the printed plywoodat an ambient temperature, a coating material for forming aphotocatalyst layer was prepared by dispersing titania sol acidifiedwith nitric acid containing 20% by weight of titanium dioxide intosilica sol acidified with nitric acid containing 20% silicon oxide inthe presence of a surfactant. Using this coating material and a barcoater No. 7, the coating material was applied on the surface of theadhesive layer and was dried at 100° C. for 30 min. to obtain aphotocatalyst-carrying printed plywood (Sample No. 17).

Example 91 Synthetic Timbers

The solution for forming an adhesive layer used in the example 90 wasdiluted with a mixed solution of xylene and isopropanol (mixing ratio,50:50) to a concentration of 5% by weight on the solid component basis.A synthetic timber, Esron Neolamber FFU-50, manufactured by SekisuiChemical Industry Co., Ltd. and cut into a piece with a dimension of 7cm×7 cm was dipped into the diluted solution prepared above, pulled outtherefrom and dried at 100° C. for 120 min. to form an adhesive layer onthe surface of the timber. The timber on which the adhesive layer wasformed was then dipped into a solution prepared by diluting the coatingmaterial for forming a photocatalyst layey used in the exmple 90 withion-exchanged water to a concentration of 10% by weight, pulled outtherefrom and dried at 100° C. for 120 min. to obtain aphotocatalyst-carrying synthetic timber (Sample No. 18).

Example 92 Wooden Doors

An indoor use wooden door (Type 38 RC0202-IR6, Oak pattern) manufacturedby Daiken Kogyo C., Ltd. was cut into a piece with a dimension of 7 cm×7cm, and the piece was applied with a solution prepared by mixingpolysiloxane (Methyl Silicate 51, manufactured by Colcoat Co., Ltd.) 20%by weight based on the weight of acryl-silicon resin (mixing ratio,50:50) containing 10% by weight of acryl-silicon resin which comprises3% by weight of silicon according to the dipping method similar to theone as described in the example 91 to form an adhesive layer and wasdried at 100° C. for 20 min. After cooling the piece at an ambienttemperature, a coating material for forming a photocatalyst layer wasprepared by dispersing titania sol acidified with nitric acid containing5% by weight of titanium dioxide into silica sol acidified with nitricacid containing 5% by weight of silicon oxide in the presence of asurfactant. This coating material was applied onto the surface of theadhesive layer by employing the dipping method described above and driedat 100° C. for 20 min. to obtain a photocatalyst-carrying wooden door.

Evaluation for Photocatalytic Activity

Photocatalytic activity of the samples 1 through 19 was evaluatedrespectively, and the results in the evaluation were presented in Table9.

TABLE 9 Initail Total Aldehyde Salad Oil Anti- Adhesvie Ray Trans-Decomposing Decomposing microbial Property Dur- missibity % ActivityActivity Activity Points ability pt Sample 1  85% A A A 10 Points 10 ptSample 2 65 B A — 5% or less Same as weight reduc- Initail tion by 10Adhesive min. ultra- Property sonification Sample 3 90 B B A 10 10Sample 4 — B A A 10 10 Sample 5 90 A A A 10 10 Sample 6 — B A A 10 10Sample 7 — B A A 10 10 Sample 8 95 B B A 10 10 Sample 9 — A A A *1 *1Sample 10 — A A A *1 *1 Sample 11 — B A A *1 *1 Sample 12 — B A A *1 *1Sample 13 — A A A 10 10 Sample 14 — B A A 10 10 Sample 15 — A A A 10 10Sample 16 — B A B  8  8 Sample 17 — B A A  8  8 Sample 18 — A A A 10 10Sample 19 — A A A 10 10 *1: Since basic grain tape method could not beemployed, the surface of the sticking tape was observed, however, noadhesion of the photocatalyst layer was recognized.

Industrial Use

The photocatalyst-carrying structure according to the present inventionhas high photocatalytic activity, and glass, plastics, metallicmaterials, cloth fabrics, timbers and wooden materials, whichrespectively carry a photocatalyst being resistant to deterioration andhighly durable, can be useful for lens, various types of window glass,adhesive films, sheets for decoration, wall papers, curtains,construction materials, such as blinds, interior goods, etc.

What is claimed is:
 1. A photocatalyst-carrying structure comprising aphotocatalyst layer, an adhesive layer and a substrate, wherein theadhesive layer is disposed between the photocatalyst layer and thesubstrate and comprises a silicon-modified resin, the adhesive layercontaining from 2 to 60% by weight silicon; a resin containing colloidalsilica, wherein the adhesive layer comprises from 5 to 40% by weight ofsaid colloidal silica; or a resin containing polysiloxane, which is apolycondensation product of a compound represented by a formula (1)SiCln₁(OH)n₂R¹n₃ (OR²)n₄  (1), wherein R¹ is an alkyl having 1-8 carbonatoms and is unsubstituted or substituted by amino, carboxyl or chlorineatom; R² is an alkyl having 1-8 carbon atoms or an alkoxy-substitutedalkyl having 1-8 carbon atoms; n₁ is an integer, 0, 1 or 2; n₂ and n₃are each independently an integer, 0, 1, 2, or 3; n₄ is an integer, 2,3, or 4; and n₁+n₂+n₃+n4=4, wherein the resin comprises from 3 to 60% byweight polysiloxane; and wherein the photocatalyst layer comprises aphotocatalyst particle and 25 to 95% by weight of a metal oxide gel or ametal hydroxide gel.
 2. The photocatalyst-carrying structure accordingto claim 1, wherein the silicon-modified resin used for the adhesivelayer is acryl-silicon resin.
 3. The photocatalyst-carrying structureaccording to claim 1, wherein the adhesive layer is composed of a resincontaining polysiloxane, and said polysloxane is made of either ahydrolyzed product of silicon alkoxide containing at least one C₁-C₅alkoxy or a compound prepared via the said hydrolyzed product.
 4. Thephotocatalyst-carrying structure according to claim 1, wherein theadhesive layer is made of silicon-modified resin containingpolysiloxane.
 5. The photocatalyst-carrying structure according to claim1, wherein the adhesive layer is made of a resin containing colloidalsilica and the diameter of the particles of the colloidal silica is 10nm or less.
 6. The photocatalyst-carrying structure according to claim1, wherein the adhesive layer is made of silicon-modified resincontaining colloidal silica.
 7. The photocatalyst-carrying structureaccording to claim 1, wherein the metal oxide gel or the metal hydroxidegel contained in the photocatalyst layer is gel and their specificsurface area dried at 150° C. is 100 m²/g or more, and is composed ofone or more gels of metals selected from a group consisting of silicon,aluminium, titanium, zirconium, magnesium, niobium, tantarum, tungstenand tin, respectively.
 8. The photocatalyst-carrying structure accordingto claim 1, wherein the photocatalyst layer is a photocatalyst complexcomposed of more than 2 kinds of metal oxide gels or metal hydroxidegels and a phohtocatalyst, and the adhesive property of the complexafter dipping it into boiling water which shows an electroconductivityof 200 μS/cm at 20° C. is expressed as an evaluated-point of 6 or moreaccording to cross-cut Scotch tape test provided in JIS K5400.
 9. Thephotocatalyst-carrying structure according to claim 8, wherein thephotocatalyst layer is composed of a photocatalyst complex, whichcomprises oxide gel or hydroxide gel of one or more metals selected froma group consisting of aluminium, titanium, zirconium and niobium, andsilicon, and has a specific surface area after drying at 150° C. of 50m²/g or more.
 10. The photocatalyst-carrying structure according toclaim 1, wherein the photocatalyst layer is composed of a photocatalystcomplex which contains either silicon-modified resin or silane compound10 to 50% by weight, either a metal oxide gel or a metal hydroxide gelfrom 15 to 85% by weight on the solid component basis and aphotocatalyst from 5 to 75% by weight, and the photocatalyst complex hasan adhesive property of point 6 or more expressed from the criterionaccording to cross-cut Scotch tape test provided in JIS K5400 afterdipping it for 15 min. into boiling water which shows anelectroconductivity of 200 μS/cm at 20° C.
 11. Thephotocatalyst-carrying structure according to claim 10, wherein thesilicon-modified resin or the silane compound contained in thephotocatalyst layer is acryl-silicon resin, epoxy-silicon resin or asilane coupler.
 12. The photocatalyst-carrying structure according toclaim 1, characterized in that the adhesive property of the structureafter exposing it to black light radiation of which ultraviolet lightintesity is 3 mW/cm² for 500 hours at 40° C. and 90% R.H. is evaluatedas point 6 or more according to the criterion of cross-cut Scotch tapetest provided in JIS K5400.
 13. A photocatalyst-carrying glass,characterized in that the glass has a constitution wherein an adhesivelayer is provided in between a photocatalyst layer and a substrate, andthe adhesive layer and the photocatalyst layer described in claim 1 areused therein.
 14. A photocatalyst-carrying plastic molding which has astructure wherein an adhesive layer is provided in between aphotocatalyst layer and a plactic molding, and the photocatalyst layerand the adhesive layer used therein are the ones described in claim 1.15. A sticking film prepared by applying a sticker onto the back side ofthe photocatalyst-carrying plastic film described in claim
 14. 16. Aphotocatalyst-carrying cloth which has a structure wherein an adhesivelayer is provided in between a photocatalyst layer and a substrate, andthe photocatalyst layer and the adhesive layer used therein are the onesdescribed in claim
 1. 17. A photocatalyst-carrying metal which has astructure wherein an adhesive layer is provided in between aphotocatalyst layer and the metal, and the photocatalyst layer and theadhesive layer used therein are the ones described in claim
 1. 18. Aphotocatalyst-carrying timber and a photocatalyst-carrying woodenmaterial which respectively has a structure wherein an adhesive layer isprovided in between a photocatalyst layer and the timber or the woodenmaterial, and the photocatalyst layer and the adhesive layer usedtherein are the ones described in claim
 1. 19. The structure of claim 1wherein the adhesive layer comprises a silicon modified resin.
 20. Thestructure of claim 1 wherein the adhesive layer comprises a resincontaining colloidal silica.
 21. The structure of claim 1 wherein theadhesive layer comprises a resin comprising polysiloxane.
 22. A coatingmaterial of a photocatalyst comprising 0.001 to 5% by weight siliconcompounds; 0.1 to 30% by weight of a metal oxide sol and/or a metalhydroxide sol, on the solid component basis and from 0.1 to 30.0% byweight on the solid component basis a photocatalyst powder and/or sol.23. The coating material of a photocatalyst according to claim 22,wherein the silicon compound is an alkoxy silane compound represented bya general formula (2), SiR³n5(OR⁴)_(4-n5)  (2), wherein R³ is an alkylhaving 1-8 carbon atoms optionally substituted with amino, chlorine atomor carboxy, R⁴ is alkyl having 1-8 carbon atoms or alkoxy-substitutedalkyl having 1-8 carbon atoms, and n₅ is 0, 1, 2 or 3, or one or more ofthe hydrolized products of the such compound.
 24. The coating materialof a photocatalyst according to claim 22, characterized in that themetal oxide sol and/or the matal hydroxide sol comprise a metal selectedfrom a group consisting of silicon, aluminium, titanium, zirconium,niobium, tantalum, magnesium, tungsten and tin, and the specific surfacearea of such sol after drying at 150° C. is 50 m²/g or more,respectively.
 25. The coating material of a photocatalyst according toclaim 22, characterized in that the silicon compound is composed of oneor more compounds selected from a group consisting of tetramethoxysilane, tetraethoxy silane, methyl trimethoxy silane, methyl triethoxysilane and their hydrolized products.
 26. A coating of a photocatalystused for producing a photocatalyst-carrying structure wherein anadhesive layer is disposed between a photocatalyst layer and a substratewherein the coating comprises two coating materials (1) and (2), wherein(1) is a coating material for forming said adhesive layer and wherein(1) comprises a resin component, said resin component comprising from 1to 50% by weight of a silicon-modified resin containing 2-60% by weightof silicon and either a resin containing 3-60% by weight of polysiloxaneor a resin containing 5-40% by weight of colloidal silica, and (2) acoating material for forming a photocatalyst layer onto the adhesivelayer comprise 0.001-5% by weight of a silicon compound, 0.1-30% byweight of a metal oxide sol and/or a metal hydroxide sol on the solidcomponent basis and 0.1-30% by weight of a photocatalyst powder and/orsol on the solid component basis.
 27. The coating material of aphotocatalyst according to claim 26, wherein the resin contained in thecoating material for forming an adhesive layer is a resin containingpolysiloxane, and said polysiloxane is the hydrolized product of alkoxysilane with an alkoxy group having 1-5 carbon atoms or an other compoundproduced from said hydrolized product.
 28. The coating material of aphotocatalyst according to claim 26, wherein the resin contained in thecoating material for forming an adhesive layer is a resin containingcolloidal silica, and the diameter of said colloidal silica is 10 nm orless.
 29. The coating material of a photocatalyst according to claim 26,wherein the resin contained in the coating material for forming anadhesive layer is silicon-modified resin containing polysiloxane. 30.The coating material of a photocatalyst according to claim 26, whereinthe resin contained in the coating material for forming an adhesivelayer is silicon-modified resin containing colloidal silica.